Chapter XVIII: Section II: DICYRTIDA, Haeckel, 1862, Monogr. d. Radiol., pp. 280, 296 (4)

Cephalis small, subspherical, with small circular pores and a large conical horn of twice the length, and some accessory spines. Thorax thorny, flatly campanulate, with twelve stout curved ribs, which at the peristome are prolonged into twelve slender, curved feet of twice the length; four of them are centrifugal prolongations of the four cortinar beams separating the four large meshes of the collar septum; eight other ribs are secondary, interpolated in pairs between the former. At the base of the thorax are twelve large triangular holes between the ribs; the other network is irregular, with polygonal meshes.

_Dimensions._--Cephalis 0.03 diameter, thorax 0.05 long, 0.12 broad.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

11. _Acanthocorys polypodia_, n. sp.

Cephalis small, hemispherical, with small, roundish pores and divergent radial spines. Thorax flatly conical, spiny, with twenty to twenty-four divergent, straight ribs, which in the proximal {1265}third are separated by the same number of large, triangular meshes, in the middle third connected by irregular network, in the distal third free.

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.15 broad.

_Habitat._--Central Pacific, Station 273, depth 2350 fathoms.

Genus 564. _Arachnocorys_,[181] Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 837.

_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with numerous radial ribs in the wall of the pyramidal thorax, prolonged into divergent terminal feet. Network double, with an arachnoidal outer mantle around the inner lattice-shell. Cephalis commonly with numerous horns.

The genus _Arachnocorys_ has been derived from the preceding _Acanthocorys_, by development of numerous external siliceous threads which connect the radial horns of the cephalis with the secondary spines arising from the thoracic ribs. In this way there becomes formed an outer arachnoidal framework, enveloping loosely, like a delicate mantle, the inner primary lattice-shell.

Subgenus 1. _Arachnocorallium_, Haeckel.

_Definition._--Thorax with six divergent ribs or radial beams (three primary or perradial, alternating with three secondary or interradial).

1. _Arachnocorys hexaptera_, n. sp.

_Arachnocorys circumtexta_ (juv.?), R. Hertwig, 1879, Organism. d.
Radiol., p. 79, Taf. viii. fig. 2_a_.

Cephalis large, subspherical, with irregular, polygonal pores, and numerous bristle-shaped spines twice the length; on the centre of the top a single larger vertical horn. Thorax flatly conical, with six strong and straight widely divergent ribs, which in the proximal half are separated by six large holes, in the distal half connected by a broad ring of irregular network. From each rib arises a perpendicular branch, and these branches are connected together, and with the spines of the cephalis, by arachnoidal network.

_Dimensions._--Cephalis 0.04 diameter, thorax 0.08 long, 0.24 broad.

_Habitat._--Central Pacific, Station 266; Mediterranean, surface.

2. _Arachnocorys discoides_, n. sp.

Cephalis small, pyramidal, with irregular, roundish pores and numerous thin spines, on the top a single larger vertical horn. Thorax very flat, nearly discoidal, with six strong and straight ribs, {1266}which by communication of few larger and numerous smaller branches form an irregular network with polygonal meshes. From each of the six ribs arise two or three larger, perpendicular branches of half the length, and from the network numerous smaller spines. All these dorsal spines of the shell are connected by a dense arachnoidal wicker-work.

_Dimensions._--Cephalis 0.02 diameter, thorax 0.04 long, 0.3 broad.

_Habitat._--Central Pacific, Station 271, surface.

Subgenus 2. _Arachnocoronium_, Haeckel.

_Definition._--Thorax with nine divergent ribs or radial beams, three of which are primary or perradial, the other six secondary or interradial. (Sometimes eight or ten occur instead of the nine normal ribs.)

3. _Arachnocorys circumtexta_, Haeckel.

_Arachnocorys circumtexta_, Haeckel, 1862, Monogr. d. Radiol., p. 304,
Taf. vi. figs. 9-11.

_Arachnocorys circumtexta_, R. Hertwig, 1879, Organism. d. Radiol., p.
78, Taf. viii. fig. 2.

Cephalis large, subspherical, with numerous roundish pores, and eight to ten slender, conical horns twice the length. Thorax flatly conical, with nine strong, straight, widely divergent, conical feet, each of which bears in the middle of its outer side a perpendicular ascending branch of half the length. These branches and the horns of the cephalis are connected by very thin, parallel, arachnoidal threads. Network of the thorax irregular, with nine larger triangular holes at the base. Collar septum with numerous, irregular, roundish pores.

_Dimensions._--Cephalis 0.04 to 0.05 diameter, thorax 0.08 to 0.12 long, 0.15 to 0.25 broad.

_Habitat._--Mediterranean (Messina); Atlantic, Stations 347 to 354, surface.

4. _Arachnocorys enneaptera_, n. sp.

Cephalis large, campanulate, with irregular, polygonal pores, two larger stout pyramidal and numerous slender, bristle-shaped horns. Thorax of the same structure as in the preceding species, only the nine basal holes are of twice the size; the lower network denser (as in _Clathrocanium diadema_, Pl. 64, fig. 2). Collar septum with numerous, irregular, roundish pores.

_Dimensions._--Cephalis 0.05 diameter, thorax 0.12 long, 0.22 broad.

_Habitat._--Tropical Atlantic, Station 338, surface.

5. _Arachnocorys araneosa_, n. sp. (Pl. 56, fig. 11).

Cephalis large, subspherical, with circular, subregular, hexagonally framed pores, and twenty to thirty slender, cylindrical, straight radial spines. Thorax flatly conical, nearly of the same shape as in the two preceding species, but with nine longer ribs, and more irregular, broader network between them. From the middle of each rib arises, nearly horizontally, a strong branch, which is directed {1267}outwards. These branches are connected with the spines of the cephalis as well as with the distal half of the ribs, by dense and delicate arachnoidal network, composed of parallel, very thin, siliceous threads (in fig. 11 only partially represented). Collar septum with numerous irregular, roundish pores.

_Dimensions._--Cephalis 0.04 diameter, thorax 0.1 long, 0.2 broad.

_Habitat._--Central Pacific, Station 270 to 274, surface.

6. _Arachnocorys arachnodiscus_, n. sp.

Cephalis small, campanulate, conical, with a single very large conical central horn, and numerous smaller accessory spines. Thorax in form and structure similar to that of the three preceding species, but much flatter, being nearly discoidal. The meshes of the network are smaller and more numerous, irregularly polygonal, and the nine basal holes little larger. Collar septum with four large meshes (as in Pl. 60, fig. 6).

_Dimensions._--Cephalis 0.25 long, 0.3 broad; thorax 0.04 long, 0.24 broad.

_Habitat._--North Pacific, Station 248, surface.

7. _Arachnocorys trifida_, n. sp.

Cephalis large, campanulate, with irregular, roundish pores and numerous ramified spines; in the centre of the top a larger pyramidal oblique horn of twice the length. Thorax cap-shaped, flatly vaulted, with nine strong convex ribs, prolonged into slender free feet. Three of these nine ribs are the centrifugal prolongations of the three cortinar bars (united in the centre of the collar stricture, separating its three large cortinar meshes); the other six are diverging lateral branches of the former, arising in pairs at both sides of its base. All nine ribs are connected by delicate arachnoidal network with irregular polygonal meshes. From its surface arise thin bristles, and from the base of each main rib a stout, perpendicular branch. All these dorsal spines are connected by irregular, arachnoidal wicker-work, covering thorax and cephalis. (A remarkable primitive species?)

_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.07 long, 0.18 broad.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

Subgenus 3. _Arachnocorythium_, Haeckel.

_Definition._--Thorax with a variable number of radial ribs (twelve to twenty or more), prolonged into free terminal feet.

8. _Arachnocorys polyptera_, n. sp.

Cephalis large, subspherical, with irregular, roundish pores and numerous radial spines. Thorax flatly conical, with numerous radial ribs (twenty to thirty), which are in the distal half free, in the proximal half connected by delicate arachnoidal wicker-work, with polygonal, irregular meshes. From its dorsal face arise numerous radial spines, which are connected together, and with the cephalic spines, by very thin and numerous threads, parallel between every two spines. Similar to {1268}_Arachnocorys araneosa_ (Pl. 56, fig. 11), but differing in the structure of the cephalis, and in the greater number of the ribs and spines.

_Dimensions._--Cephalis 0.04 diameter, thorax 0.12 long, 0.24 broad.

_Habitat._--South Pacific, Station 300, depth 1375 fathoms.

Genus 565. _Anthocyrtoma_,[182] n. gen.

_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without thoracic ribs, with six terminal feet around the mouth. Cephalis free, with an apical horn.

The genus _Anthocyrtoma_ and the four following genera form together the peculiar group of Carpocanida, comprising all those Sethophormida in which the original thoracic ribs are lost, and only the terminal feet remain. _Anthocyrtoma_ is the simplest form of this group, possessing only six terminal feet, three primary perradial, and three alternating, secondary, interradial. It may be directly derived either from _Lychnocanium_, by interpolation of three interradial feet, or from _Hexaspyris_ by loss of the sagittal ring.

1. _Anthocyrtoma serrulata_, Haeckel.

_Anthocyrtis serrulata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 66, Taf. vi. fig. 7.

Shell pear-shaped, rough, with obliterated collar stricture. Length of the two joints = 1 : 4, breadth = 1 : 3. Cephalis ovate, with very small pores, and a stout conical horn of the same length. Abdomen inflated, truncate, with larger, regular, circular pores, twice as broad as the constricted mouth. Six feet vertical, parallel, serrate, all of the same size, about as long as the cephalis.

_Dimensions._--Cephalis 0.06 long, 0.05 broad; thorax 0.2 long, 0.17 broad.

_Habitat._--Fossil in Barbados.

2. _Anthocyrtoma alterna_, n. sp.

Shell pear-shaped, smooth, with distinct collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 6. Cephalis hemispherical, with a slender conical horn of twice the length. Abdomen inflated, subglobular, with regular, circular, hexagonally framed pores, three times as broad as the narrow, constricted mouth. Six feet conical, smooth, somewhat divergent, alternating, of different sizes; the three larger (perradial) half as long as the shell, and twice as long as the three smaller (interradial). (Similar to _Anthocyrtis ventricosa_.)

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.15 long, 0.18 broad.

_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms.

{1269}Genus 566. _Anthocyrtis_,[183] Ehrenberg, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1847, p. 54.

_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without thoracic ribs, with nine terminal feet around the mouth. Cephalis free, with an apical horn.

The genus _Anthocyrtis_ (in the original definition of Ehrenberg) contained all Dicyrtida without thoracic ribs, with terminal feet. We here restrict the definition to those Sethophormida in which the number of free terminal feet is constantly nine (three primary perradial and three alternate pairs of secondary interradial feet). _Anthocyrtis_ may be derived either directly from _Patagospyris_ by loss of the sagittal ring, or from _Lychnocanium_ by interpolation of three secondary feet.

Subgenus 1. _Anthocyrtella_, Haeckel.

_Definition._--Feet of the peristome-corona divergent, their basal distance less than their terminal distance.

1. _Anthocyrtis mespilus_, Ehrenberg.

_Anthocyrtis mespilus_, Ehrenberg, 1854, Taf. xxxvi. fig. 13; Abhandl. d.
k. Akad. d. Wiss. Berlin, 1875, p. 66, Taf. vi. fig. 4 (not 5).

Shell smooth, with distinct collar stricture. Length of the two joints = 1 : 5, breadth = 2 : 6. Cephalis hemispherical, with a stout pyramidal horn of twice the length. Thorax nearly hemispherical, with regular, circular, quincuncial pores. Mouth scarcely constricted, with nine divergent, triangular, lamellar feet, about as long as the thorax.

_Dimensions._--Cephalis 0.012 long, 0.02 broad; thorax 0.05 long, 0.06 broad.

_Habitat._--Fossil in Barbados.

2. _Anthocyrtis furcata_, Ehrenberg.

_Anthocyrtis furcata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. vi. fig. 2.

Shell smooth, with deep collar stricture. Length of the two joints = 1 : 5, breadth = 2 : 6. Cephalis hemispherical, with a short pyramidal horn of half the length. Thorax hemispherical, with large, irregular, roundish pores. Mouth scarcely constricted, with nine divergent, curved, slender feet, which are about as long as the shell, and forked at the distal end.

_Dimensions._--Cephalis 0.01 long, 0.02 broad; thorax 0.05 long, 0.06 broad.

_Habitat._--Fossil in Barbados.

{1270}3. _Anthocyrtis butomus_, n. sp.

Shell thorny, with obliterated collar stricture. Length of the two joints = 2 : 6, breadth = 2 : 7. Cephalis ovate, with very small and scarce pores, and a conical horn of the same length. Thorax inflated, pear-shaped, with regular, circular, quincuncial pores. Mouth about half as broad, constricted, with nine divergent, broad, nearly square, lamellar feet, half as long as the thorax (similar to _Anthocyrtis serrulata_, Ehrenberg, _loc. cit._, Taf. vi. fig. 7).

_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.12 long, 0.14 broad.

_Habitat._--Central Pacific, Station 265, depth 2900 fathoms.

4. _Anthocyrtis ventricosa_, Ehrenberg.

_Anthocyrtis ventricosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 66, Taf. viii. fig. 1.

Shell thorny, with obliterated collar stricture. Length of the two joints = 1 : 7, breadth = 2 : 7. Cephalis hemispherical, hyaline, without pores, with a slender, conical horn, of about the same length. Thorax inflated, pear-shaped or subspherical, with regular, circular, quincuncial pores. Mouth only one-third as broad, much constricted, with nine divergent, slender, conical feet, about one-fifth as long as the diameter of the shell (partly broken off in Ehrenberg's figure).

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.14 long, 0.14 broad.

_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms; also fossil in Barbados.

Subgenus 2. _Anthocyrtissa_, Haeckel.

_Definition._--Feet of the peristome-corona parallel, vertical; their basal and terminal distances equal.

5. _Anthocyrtis ophirensis_, Ehrenberg.

_Anthocyrtis ophirensis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 285, Taf. ix. fig. 13.

Shell smooth, with slight collar stricture. Length of the two joints = 2 : 4, breadth = 1 : 5. Cephalis ovate, with irregular, roundish pores, and a pyramidal, excentric, vertical horn of the same length. Thorax campanulate, with delicate network of large, regular, hexagonal pores. Mouth scarcely constricted, with nine parallel, vertical, conical feet, about as long as the cephalis. (In the specimen figured by Ehrenberg only seven feet are represented, two being broken off; two other specimens of this species, captured by Rabbe, exhibited nine regularly disposed feet.)

_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.08 long, 0.1 broad.

_Habitat._--Indian Ocean, Zanzibar (Pullen); Madagascar (Rabbe), surface.

{1271}6. _Anthocyrtis lauranthus_, n. sp.

Shell smooth with slight collar stricture. Length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis ovate, with large, roundish pores, and a conical horn of twice the length. Thorax inflated, campanulate, with regular, circular, hexagonally framed pores. Mouth two-thirds as broad, little constricted, with nine parallel, vertical, broad, lamellar, triangular feet, half as long as the cephalis.

_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.1 long, 0.12 broad.

_Habitat._--Central Pacific, Station 266 to 270, depth 2550 to 2925 fathoms.

7. _Anthocyrtis grossularia_, Ehrenberg.

_Anthocyrtis grossularia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. vi. fig. 6.

Shell spiny, with deep collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 4. Cephalis subspherical, thorny, with a conical horn of the same length. Thorax ovate, spiny, with numerous densely-crowded, subregular, circular pores. Mouth about half as broad, constricted, with nine parallel, vertical, slender, conical feet, about as long as the cephalis.

_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.2 long, 0.18 broad.

_Habitat._--Fossil in Barbados.

8. _Anthocyrtis subglobosa_, n. sp.

Shell spiny, with deep collar stricture. Length of the two joints = 1 : 7, breadth = 1 : 7. Cephalis subspherical, with a conical horn twice the length. Thorax nearly spherical, with small and very numerous, regular, circular pores. Mouth only one-third as broad, constricted, with nine parallel, vertical, square, lamellar feet, about twice as long as the cephalis.

_Dimensions._--Cephalis 0.03 long, 0.035 broad; thorax 0.2 long, 0.2 broad.

_Habitat._--South Pacific, Station 297, depth 1775 fathoms.

Subgenus 3. _Anthocyrtura_, Haeckel.

_Definition._--Feet of the peristome-corona convergent, their basal distance greater than their terminal distance.

9. _Anthocyrtis enneaphylla_, n. sp.

Shell smooth, with sharp collar stricture. Length of the two joints = 1 : 6, breadth = 1 : 5. Cephalis subspherical, with a conical horn twice the length, nearly hyaline, with very small and scarce pores. Thorax nearly spherical, with regular, circular, quincuncial pores. Mouth only {1272}half as broad, with nine broad, triangular feet, twice as long as the cephalis, and curved inwards, convergent towards the main axis.

_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.11 long, 0.12 broad.

_Habitat._--South Atlantic, Station 332, depth 2200 fathoms.

10. _Anthocyrtis ovata_, n. sp. (Pl. 62, fig. 13).

Shell smooth, with slight collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 3. Cephalis ovate, with numerous small pores, and an excentric conical horn of the same length. Thorax ovate, with regular, circular, quincuncial pores. Mouth nearly of the same breadth, scarcely constricted, with nine triangular, widely-separated feet, about as long as the cephalis, and convergent towards the main axis.

_Dimensions._--Cephalis 0.035 long, 0.03 broad; thorax 0.15 long, 0.1 broad.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

Genus 567. _Anthocyrtium_,[184] n. gen.

_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without thoracic ribs, with numerous terminal feet around the mouth (twelve to fifteen or more). Cephalis free, with an apical horn.

The genus _Anthocyrtium_ has been derived from the two preceding genera by further multiplication of the terminal feet, the number of which is at least twelve to fifteen, often twenty or more. It may be that some species have arisen directly from _Patagospyris_ by loss of the sagittal ring.

Subgenus 1. _Anthocyrtarium_, Haeckel.

_Definition._--Feet of the peristome-corona divergent, their basal distance less than their terminal distance.

1. _Anthocyrtium chrysanthemum_, n. sp. (Pl. 62, fig. 14).

Shell smooth, with distinct collar stricture. Length of the two joints = 3 : 7, breadth = 4 : 9. Cephalis hemispherical, with small, circular pores, and a large, straight, cylindro-conical horn, about as long as the shell. Thorax campanulate, hemispherical, with six to eight transverse rows of squarish pores, increasing in size downwards. Mouth little constricted, with twelve to fifteen divergent, curved, slender feet, about as long as the thorax.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.07 long, 0.09 broad.

_Habitat._--Central Pacific, Station 270 to 274, depth 2350 to 2925 fathoms.

{1273}2. _Anthocyrtium centaurea_, Haeckel.

_Anthocyrtis mespilus_, var. _major_, Ehrenberg, 1875, Abhandl. d. k.
Akad. d. Wiss. Berlin, p. 66, Taf. vi. fig. 5.

Shell smooth, with sharp collar stricture. Length of the two joints = 2 : 6, breadth = 3 : 7. Cephalis hemispherical, with irregular, roundish pores, and a very large pyramidal horn, longer than the shell, with contorted edges. Thorax hemispherical, with six to eight transverse rows of regular, circular pores of equal size. Mouth little constricted, with fifteen to twenty divergent, curved, slender feet, about as long as the shell.

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.07 broad.

_Habitat._--Fossil in Barbados.

3. _Anthocyrtium anthemis_, n. sp.

Shell papillate, with obliterated collar stricture. Length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis hemispherical, with very small and scarce pores, and a conical horn of the same length. Thorax conical, as long as broad, with conical papillæ, and eight to ten transverse rows of roundish pores, gradually increasing in size downwards. Mouth scarcely constricted, with fifteen to twenty divergent, straight, conical feet, half as long as the thorax.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.09 broad.

_Habitat._--North Pacific, Station 244, depth 2900 fathoms.

4. _Anthocyrtium collare_, Haeckel.

_Anthocyrtis collaris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. vi. fig. 8.

Shell rough, conical, with obliterated collar stricture. Length of the two joints = 3 : 5, breadth = 4 : 7. Cephalis conical, with a pyramidal horn of the same length, and with two transverse rows of rather oblong, narrow pores. Thorax truncate, conical, in the lower part thorny, with six to eight transverse rows of regular, circular pores, increasing in size downwards.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.05 long, 0.07 broad.

_Habitat._--Fossil in Barbados.

5. _Anthocyrtium adonis_, n. sp. (Pl. 62 fig. 20).

Shell rough, with sharp collar stricture. Length of the two joints = 3 : 10, breadth = 4 : 12. Cephalis subspherical, with very small circular pores, and a very long, straight cylindrical, horn, twice to three times as long as the shell. Thorax inflated, ovate, or subspherical, with small regular, circular, hexagonally-framed pores. Mouth strongly constricted, half as broad as the thorax, with fifteen to {1274}twenty divergent, broad, lamellar, rectangular feet, as long as the thorax, and so densely placed that their margins come in contact with one another.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.12 broad.

_Habitat._--Central Pacific, Station 263 to 268, depth 2650 to 3000 fathoms.

6. _Anthocyrtium anemone_, n. sp.

Shell spiny, with sharp collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 4. Cephalis subspherical, with a conical horn of half the length, hyaline, without pores. Thorax spiny, pear-shaped, inflated, with small and numerous, regular, circular pores. Mouth constricted, half as broad as the thorax, with twelve to fifteen divergent, slender, conical, denticulate feet, half as long as the thorax.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.14 long, 0.12 broad.

_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil in Barbados.

Subgenus 2. _Anthocyrtonium_, Haeckel.

_Definition._--Feet of the peristome-corona parallel, vertical; their basal and apical distances equal.

7. _Anthocyrtium campanula_, n. sp. (Pl. 62, fig. 17).

Shell smooth, with deep collar stricture. Length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis spherical, with a conical horn of the same length. Thorax campanulate, thin-walled, with delicate network of regular, hexagonal pores and thin bars. Mouth little constricted, with twenty to twenty-four parallel, vertical, lanceolate feet, about as long as the cephalis.

_Dimensions._--Cephalis 0.03 diameter, thorax 0.09 long, 0.1 broad.

_Habitat._--South Pacific, Station 302, depth 1450 fathoms.

8. _Anthocyrtium reticulatum_, Haeckel.

_Thyrsocyrtis reticulata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 84, Taf. xii. fig. 10.

Shell rough, with sharp collar stricture. Length of the two joints = 1 : 2, breadth = 1 : 3. Cephalis hemispherical, with a prismatic, denticulate horn of the same length, and small, irregular pores. Thorax campanulate, thorny, thin-walled, with delicate network of irregular, polygonal pores. Mouth little constricted, with twelve (or more) small, parallel, vertical, triangular feet, shorter than the cephalis.

_Dimensions._--Cephalis 0.015 long, 0.02 broad; thorax 0.04 long, 0.06 broad.

_Habitat._--Fossil in Barbados.

{1275}9. _Anthocyrtium leptostylum_, Haeckel.

_Anthocyrtis leptostyla_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. vi. fig. 1.

Shell thorny, with slight collar stricture. Length of the two joints = 1 : 5, breadth = 2 : 4. Cephalis hemispherical, with small, scarce pores and a slender conical horn of the same length. Thorax spiny, with regular, circular, quincuncial pores. Mouth constricted, half as broad, with twelve to eighteen slender, parallel, vertical feet, about as long as the cephalis.

_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.1 long, 0.08 broad.

_Habitat._--Central Pacific, Stations 266 to 270, depth 2550 to 2925 fathoms; also fossil in Barbados.

10. _Anthocyrtium hispidum_, Haeckel.

_Anthocyrtis hispida_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. viii. fig. 2.

_Anthocyrtis hispida_, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol.
xxxvi. p. 540, Taf. xxxiii. fig. 30.

Shell thorny, with sharp collar stricture. Length of the two joints = 1 : 4, breadth = 2 : 5. Cephalis hemispherical, hyaline, with few very small pores, or without any; with a stout conical horn of twice the length. Thorax spiny, with regular, circular, hexagonally-framed pores (half as broad as the bars between them). Mouth wide open, scarcely constricted, with twelve to fifteen parallel, vertical, broad, lamellar, rectangular feet, reaching nearly the length of the thorax.

_Dimensions._--Cephalis 0.02 to 0.03 long, 0.03 to 0.05 broad; thorax 0.07 to 0.09 long, 0.1 to 0.12 broad.

_Habitat._--Central Pacific, Stations 263 to 265, depth 2650 to 3000 fathoms; also fossil in Barbados.

11. _Anthocyrtium turris_, n. sp.

Shell thorny, very similar to _Calocyclas turris_, Ehrenberg (1875, _loc. cit._, Taf. xviii. fig. 7), but without fenestrated abdomen. Collar stricture deep. Length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis subspherical, hyaline, without pores, with a stout conical horn of twice the length. Thorax nearly spherical, spiny, with regular, circular, quincuncial pores. Mouth little constricted, with fifteen to twenty parallel, vertical, broad, lamellar, rectangular feet, about as long as the thorax.

_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.1 long, 0.1 broad.

_Habitat._--Central Pacific, Station 265, depth 2900 fathoms.

{1276}12. _Anthocyrtium doronicum_, n. sp. (Pl. 62, fig. 18).

Shell rough, with sharp collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 3. Cephalis hemispherical, with small, circular pores and a stout conical horn of twice the length. Thorax campanulate, subcylindrical, with regular, circular, quincuncial pores, three to four times as broad as the bars. Mouth scarcely constricted, with twenty-four to thirty vertical, nearly parallel, little curved feet, which are about half as long as the shell, broad, lamellar, rectangular, and in close contact with their edges.

_Dimensions._--Cephalis 0.025 long, 0.035 broad, thorax 0.12 long, 0.1 broad.

_Habitat._--South Pacific, Station 295, depth 1500 fathoms.

Subgenus 3. _Anthocyrturium_, Haeckel.

_Definition._--Feet of the peristome-corona convergent, their basal distance greater than their apical distance.

13. _Anthocyrtium pyrum_, n. sp. (Pl. 62, fig. 12).

Shell smooth, with obliterated collar stricture. Length of the two joints = 2 : 7, breadth = 3 : 8. Cephalis hemispherical, with a small, bristle-shaped horn of half the length. Thorax inflated, subglobose, with regular, circular, quincuncial pores and thin bars. Mouth constricted, only half as broad, with fifteen to twenty small, triangular, convergent feet, shorter than the cephalis. (In another specimen the feet were twice as long, stronger and more convergent, than in the one figured.)

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.07 long, 0.8 broad.

_Habitat._--North Pacific, Station 241, depth 2300 fathoms.

14. _Anthocyrtium setosum_, Haeckel.

_Anthocyrtis setosa_, Haeckel, 1862, Monogr. d. Radiol., p. 311.

? _Lithopera setosa_, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B., B. iv.
fig. 23.

Shell spiny, with sharp collar stricture. Length of the two joints = 1 : 2, breadth = 1 : 3. Cephalis hemispherical, with a conical horn of the same length and some accessory spines. Thorax campanulate, with subregular, circular pores. Mouth little constricted, with twenty to thirty small, triangular, convergent feet, about as long as the cephalis. (In Ehrenberg's incomplete figure they are mostly broken off.)

_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.04 long, 0.06 broad.

_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms.

{1277}15. _Anthocyrtium ehrenbergii_, Haeckel.

_Anthocyrtis ehrenbergii_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 100,
Taf. iii. fig. 21, _a_, _b._

Shell smooth, with obliterated collar stricture. Length of the two joints = 3 : 10, breadth = 2 : 8. Cephalis subcylindrical, with an excentric, stout, pyramidal horn of the same length. Thorax bottle-shaped, with small, regular, circular pores of equal size. Mouth little constricted, with twenty to thirty small, triangular, convergent feet, about half as long as the cephalis.

_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.1 long, 0.08 broad.

_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte), Stöhr.

16. _Anthocyrtium zanguebaricum_, Haeckel.

_Anthocyrtis zanguebarica_, Ehrenberg, 1872, Abhandl. d. k. Akad. d.
Wiss. Berlin, p. 285, Taf. ix. fig. 12.

Shell smooth, with slight collar stricture. Length of the two joints = 3 : 10, breadth = 2 : 7. Cephalis subspherical, with an excentric conical horn of the same length. Thorax slender, ovate or bottle-shaped, with irregular, roundish pores increasing in size downwards. Mouth little constricted, with twelve to fifteen small, triangular, convergent feet, about half as long as the cephalis.

_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.1 long, 0.07 broad.

_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen.

17. _Anthocyrtium ficus_, Haeckel.

_Anthocyrtis ficus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 64, Taf. vi. fig. 3.

Shell rough, with obliterated collar stricture. Length of the two joints = 2 : 12, breadth = 3 : 10. Cephalis conical, with a large, cylindrical horn, pyramidal at the base, about as long as the thorax. Thorax subovate, truncate, papillate, with small, regular, circular, quincuncial pores of the same breadth as the bars. Mouth constricted, two-thirds as broad as the thorax, with fifteen to twenty strongly convergent, lamellar, rectangular or sword-shaped feet, nearly as long as the thorax.

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.12 long, 0.1 broad.

_Habitat._--Fossil in Barbados.

18. _Anthocyrtium flosculus_, n. sp. (Pl. 62, fig. 19).

_Anthocyrtis flosculus_, Haeckel, 1881, Prodromus et Atlas, pl. lxii.
fig. 19.

Shell ribbed, with distinct collar stricture. Length of the two joints = 1 : 4, breadth = 2 : 4. Cephalis hemispherical, with small, circular pores and a large cylindrical horn, twice as long as the thorax and half as broad at the base as the cephalis. Thorax subovate, truncate, with twenty-four to thirty longitudinal ribs and alternating rows of circular pores. Mouth constricted, two-thirds {1278}as broad as the thorax, with twenty-four to thirty slender, convergent feet, which are as long as the entire shell, with their edges in close contact and their distal ends pointed.

_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax 0.12 long, 0.12 broad.

_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 fathoms.

Genus 568. _Anthocyrtidium_,[185] Haeckel, 1881, Prodromus, p. 431.

_Definition._--#Sethophormida#, (vel Dicyrtida multiradiata aperta) without thoracic ribs, with numerous (twelve to fifteen or more) subterminal feet, which are separated from the constricted mouth by a ring of lattice-work. Cephalis free, with an apical horn.

The genus _Anthocyrtidium_ has been derived from the preceding _Anthocyrtium_ by further growth and constriction of the peristome, which becomes separated from the subterminal corona of feet by a more or less broad ring of lattice-work.

1. _Anthocyrtidium cineraria_, n. sp. (Pl. 62, fig. 16).

Shell campanulate, smooth, with obliterated collar stricture. Length of the two joints = 5 : 11, breadth = 3 : 13. Cephalis subcylindrical-ovate, with a conical straight horn of half the length. Thorax hemispherical, inflated, nearly twice as broad as the constricted mouth. Pores subregular, circular, double-contoured. Above the mouth, separated from it by two rows of pores, a corona of twelve to fifteen short conical feet, which are directed downwards, slightly curved, and as long as the cephalic horn.

_Dimensions._--Cephalis 0.05 long, 0.03 broad; thorax 0.11 long, 0.13 broad.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

2. _Anthocyrtidium ligularia_, n. sp. (Pl. 62, fig. 15).

Shell campanulate, rough, with distinct collar stricture. Length of the two joints = 1 : 4, breadth = 2 : 6. Cephalis hemispherical, with a slender, conical, slightly curved horn, about as long as the shell. Thorax hemispherical, three times as broad as the cephalis, nearly twice as broad as the constricted mouth, which is prolonged into a prominent smooth ring. Above the mouth, separated from it by one row of pores, a corona of twelve to fifteen slender linear feet, which are slightly curved, divergent, and emarginate at the truncated distal end.

_Dimensions._--Cephalis 0.015 long, 0.03 broad; thorax 0.06 long, 0.09 broad.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

{1279}3. _Anthocyrtidium matricaria_, n. sp.

Shell campanulate, rough, very similar to the preceding species, but differing in the straight, large, pyramidal horn of the cephalis (as long as the shell), and in the longer feet, which are twelve to fifteen in number, little curved at the distal end, pointed, and about as long as the shell. Length of the two joints = 2 : 6, breadth = 3 : 8. Differs from the similar _Anthocyrtium centaurea_, Ehrenberg (1875, _loc. cit._, Taf. vi. fig. 5), mainly in the prominent ring of the peristome.

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 broad.

_Habitat._--Fossil in Barbados.

Genus 569. _Carpocanium_,[186] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without thoracic ribs, with numerous terminal feet around the mouth (six to twelve or more). Cephalis hidden in the thorax, without apical horn.

The genus _Carpocanium_, very common, and rich in numerous living and fossil species, was formerly placed by me among the true Monocyrtida, since an external constriction is not visible (Monogr., 1862, p. 290). Afterwards (in 1879) Richard Hertwig demonstrated that the cavity of the ovate shell, externally simple, is divided by an internal transverse septum into two joints, the upper of which is the flat rudimentary cephalis (Organism. d. Radiol., p. 79; compare also Bütschli, 1882, _loc. cit._, p. 535). Indeed this septum, with four central crossed cortinar beams, is a true collar septum, and _Carpocanium_ has been derived from _Anthocyrtis_ or _Desmospyris_ by reduction of the cephalis, which is very flat and perfectly hidden in the uppermost part of the thorax. The apical horn is lost. If the internal septum were to become lost, the genus would pass over into _Carpocanistrum_.

Subgenus 1. _Carpocanarium_, Haeckel.

_Definition._--Peristome-corona composed of six feet (three primary perradial alternating with three secondary interradial).

1. _Carpocanium calycodes_, Stöhr.

_Carpocanium calycodes_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 96, Taf.
iii. fig. 8.

Shell urceolate, smooth, nearly twice as long as broad, with hemispherical vaulted cephalis. Length of the two joints = 3 : 16, breadth = 5 : 10. Pores regular, circular, as broad as the bars, {1280}quincuncially disposed in about five longitudinal series at each side. Mouth constricted, half as broad as the thorax. Peristome with six vertical, equilateral, triangular feet.

_Dimensions._--Cephalis 0.015 long, 0.025 broad; thorax 0.08 long, 0.05 broad.

_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta).

2. _Carpocanium setosum_, Haeckel.

_Halicalyptra setosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 160, Taf. ii. fig. 12.

Shell ovate, truncate at the mouth, thorny, exactly as long as broad. Length of the two joints = 1 : 8, breadth = 3 : 9. Cephalis hidden, with very small pores. Thorax inflated, with regular, circular pores, twice as broad as the bars, in about ten longitudinal series at each side. Mouth constricted, half as broad as the thorax. Peristome with six vertical, parallel, broad, lamellar, rectangular feet, separated by equal internals, half as long as the shell.

_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.09 broad.

_Habitat._--Fossil in Barbados.

3. _Carpocanium laeve_, Ehrenberg.

_Carpocanium laeve_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 287.

Shell subspherical, smooth, equal in length and breadth, with little vaulted, cap-shaped cephalis. Length of the two joints = 1 : 6, breadth = 4 : 7. Pores regular, circular, twice as broad as the bars, in nine longitudinal rows. Mouth constricted, only one-third as broad as the thorax. Peristome with six strong conical feet, which are slightly curved and convergent.

_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.06 long, 0.07 broad.

_Habitat._--Mediterranean (Greece); Tropical Atlantic, Station 348, depth 2450 fathoms.

4. _Carpocanium lanceolatum_, n. sp.

Shell subspherical, thorny, with perfectly hidden cephalis. Length of the two joints = 1 : 3, breadth = 1 : 3. Pores regular, circular, hexagonally framed, half as broad as the bars, in about sixteen longitudinal rows at each side. Mouth constricted, half as broad as the thorax. Peristome with six large lanceolate, vertical, lamellar feet, half as long as the shell.

_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.09 long, 0.09 broad.

_Habitat._--South Pacific, Station 300, depth 1375 fathoms.

Subgenus 2. _Carpocanidium_, Haeckel.

_Definition._--Peristome-corona composed of nine feet (three primary perradial and six secondary interradial).

{1281}5. _Carpocanium diadema_, Haeckel.

_Carpocanium diadema_, Haeckel, 1862, Monogr. d. Radiol., p. 290, Taf. v.
fig. 1.

_Carpocanium diadema_, R. Hertwig, 1879, Organism. d. Radiol., p. 79,
Taf. viii. figs. 7, 7_a_, 8, 8_a_, 8_b_.

Shell ovate, with little vaulted cephalis. Length of the two joints = 1 : 8, breadth = 3 : 6. Pores regular, circular, in about twelve longitudinal rows, twice as broad as the bars. Mouth constricted, half as broad as the thorax. Peristome with nine vertical, equilateral, triangular feet.

_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.06 broad.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; many stations, surface.

6. _Carpocanium cylindricum_, n. sp.

Shell cylindrical, with hemispherical, flatly vaulted cephalis. Length of the two joints = 1 : 4, breadth = 3 : 3. Pores regular, circular, double-contoured, as broad as the bars, in about fifteen longitudinal series. Mouth constricted, two-thirds as broad as the thorax. Peristome with nine vertical, slender, triangular, pointed feet.

_Dimensions._--Cephalis 0.02 long, 0.06 broad; thorax 0.08 long, 0.06 broad.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

7. _Carpocanium enneaphyllum_, n. sp.

Shell slenderly ovate, at the mouth truncate, thorny, with hemispherical, vaulted cephalis. Length of the two joints = 1 : 6, breadth = 2 : 4. Pores regular, circular, hexagonally framed, as broad as the bars, in about thirteen longitudinal rows. Mouth constricted, about two-thirds as broad as the thorax. Peristome with nine broad, lamellar, vertical, nearly square feet, half as long as the shell, with small intervals.

_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.09 broad.

_Habitat._--South Atlantic, Station 332, depth 2200 fathoms.

8. _Carpocanium solitarium_, Ehrenberg.

_Carpocanium solarium_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 28.

_Lithocampe solitaria_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 65.

Shell slenderly ovate, twice as long as broad, with hidden spherical cephalis, completely enclosed in the summit of the thorax. Length of the two joints = 1 : 6, breadth = 1 : 4. Pores small, regular, circular, as broad as the bars, in about eleven longitudinal rows. Mouth gradually constricted, half as broad as the thorax. Peristome with nine ovate blunt feet, which are as long as the cephalis, little curved and convergent.

_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.12 long, 0.07 broad.

_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta).

{1282}9. _Carpocanium gemmula_, n. sp.

Shell subspherical, smooth, equal in length and breadth, with hemispherical vaulted cephalis. Length of the two joints = 2 : 7, breadth = 4 : 9. Pores small, regular, circular, twice as broad as the bars, in about twenty longitudinal rows. Mouth strongly constricted, only one-fourth as broad as the thorax. Peristome with nine conical feet, which are twice as long as the cephalis, curved, and so convergent that their distal ends come nearly in contact.

_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.07 long, 0.09 broad.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

10. _Carpocanium microdon_, Ehrenberg.

_Carpocanium microdon_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 30.

Shell broad, ovate, rough, with perfectly hidden cephalis. Length of the two joints = 2 : 9, breadth = 4 : 7. Pores very small and scarce, smaller than the bars between them, irregularly scattered. Mouth constricted, one-third as broad as the thorax. Peristome with nine short, triangular, pointed, convergent feet.

_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.09 long, 0.07 broad.

_Habitat._--Mediterranean (Crete), Atlantic (Canary Islands), Station 354, surface.

Subgenus 3. _Carpocanobium_, Haeckel.

_Definition._--Peristome-corona composed of twelve or more feet.

11. _Carpocanium trepanium_, n. sp. (Pl. 52, fig. 18).

Shell subcylindrical, with flatly vaulted cephalis. Length of the two joints = 1 : 6, breadth = 3 : 4. Pores regular, hexagonal, four to six times as broad as the bars. Mouth little constricted, two-thirds as broad as the thorax. Peristome with eighteen to twenty-four large, slender, triangular, vertical feet.

_Dimensions._--Cephalis 0.02 long, 0.06 broad; thorax 0.12 long, 0.08 broad.

_Habitat._--Indian Ocean, Madagascar (Rabbe), surface.

12. _Carpocanium hexagonale_, n. sp. (Pl. 52, fig. 15).

Shell broadly ovate or subconical, with vaulted, cap-shaped cephalis. Length of the two joints = 2 : 7, breadth = 6 : 9. Thorax subglobular, truncate. Pores subregular, hexagonal, three to four times as broad as the bars. Mouth constricted, two-thirds as broad as the thorax. Peristome with twenty to twenty-five small, triangular, vertical feet.

_Dimensions._--Cephalis 0.02 long, 0.05 broad; thorax 0.07 long, 0.09 broad.

_Habitat._--Tropical Atlantic, Station 347, surface.

{1283}13. _Carpocanium petalospyris_, n. sp. (Pl. 52, fig. 19).

Shell subspherical, smooth, with perfectly hidden cephalis. Length of the two joints = 1 : 6, breadth = 3 : 6. Pores regular, circular, hexagonally framed, twice as broad as the bars, in about sixteen longitudinal rows. Mouth slightly constricted, little narrower than the thorax. Peristome with twenty to twenty-four vertical, broad, lamellar feet, which are nearly as long as the shell, at the distal end truncate, and almost in contact at their edges.

_Dimensions_.--Cephalis 0.02 long, 0.05 broad; thorax 0.11 long, 0.12 broad.

_Habitat_.--Central Pacific, Station 271, depth 2425 fathoms.

14. _Carpocanium polypterum_, Haeckel.

_Cryptoprora polyptera_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 287, Taf. ix. fig. 17.

_Carpocanium macropterum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 302.

Shell campanulate-conical, smooth, with perfectly hidden cephalis. Length of the two joints = 1 : 6, breadth = 4 : 6. Pores regular, circular, twice as broad as the bars, in about sixteen longitudinal rows. Mouth wide open, not constricted. Peristome with twenty to thirty vertical, slender, conical feet, about as long as the shell.

_Dimensions_.--Cephalis 0.01 long, 0.04 broad; thorax 0.06 long, 0.06 broad.

_Habitat_.--Indian Ocean (Zanzibar), depth 2200 fathoms (Pullen).

15. _Carpocanium palmipes_, n. sp.

Shell ovate, very thick-walled, smooth. Lower half of the subspherical cephalis hidden in the summit of the thorax, upper half free, with few small pores. Length of the two joints = 3 : 10, breadth = 3 : 10. Thorax foveolate, with oblong dimples, each of which encloses a small, circular, double-contoured pore, half as broad as the bars. Mouth little constricted, nearly as broad as the thorax. Peristome prolonged into a solid, cylindrical tube, nearly as long and as broad as the shell; the upper half of the tube is solid, the lower divided into from twelve to fifteen vertical, lamellar, pointed feet.

_Dimensions_.--Cephalis 0.03 long, 0.03 broad; thorax 0.1 long, 0.1 broad.

_Habitat_.--Western Tropical Pacific, Station 225, depth 4475 fathoms.

16. _Carpocanium peristomium_, n. sp. (Pl. 52, figs. 16, 17).

Shell ovate, smooth, with perfectly hidden, flat cephalis (fig. 17). Length of the two joints = 2 : 10, breadth = 5 : 9. Pores small and very numerous, regular, circular, as broad as the bars, in about twenty longitudinal rows. Mouth little constricted. Peristome broad; in the upper {1284}half a hyaline, circular ring, in the lower half divided into from eighteen to twenty-four triangular, curved, little convergent feet.

_Dimensions._--Cephalis 0.02 long, 0.05 broad; thorax 0.1 long, 0.09 broad.

_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; many stations, at various depths.

17. _Carpocanium coronatum_, Ehrenberg.

_Carpocanium coronatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 66, Taf. v. fig. 7.

Shell ovate, smooth, with perfectly hidden, subspherical cephalis. Length of the two joints = 2 : 9, breadth = 2 : 8. Pores small and very numerous, twice as broad as the bars, regular, circular, in about twenty longitudinal rows. Mouth little constricted, two-thirds as broad as the thorax. Peristome with twenty-five to thirty short, bristle-shaped feet, which are slightly curved, convergent, and in the upper half connected by a solid ring.

_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.09 long, 0.08 broad.

_Habitat._--Fossil in Barbados.

18. _Carpocanium dactylus_, n. sp.

Shell slenderly ovate, twice as long as broad, with flat, perfectly hidden cephalis. Length of the two joints = 1 : 12, breadth = 4 : 8. Pores subregular, circular, as broad as the bars, in about twelve longitudinal rows, separated by prominent longitudinal ribs. Mouth constricted, two-thirds as broad as the thorax. Peristome with twelve large, lanceolate, lamellar, convergent feet.

_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.12 long, 0.08 broad.

_Habitat._--South Pacific, Station 295, depth 1500 fathoms.

19. _Carpocanium irregulare_, n. sp. (Pl. 52, fig. 14).

Shell irregular, roundish, subovate, with flat and oblique, perfectly hidden cephalis. Length of the two joints = 1 : 10, breadth = 3 : 9. Pores irregularly scattered, roundish, about as broad as the bars. Mouth wide open, not at all or little constricted. Peristome with twenty to thirty long, lamellar, pointed feet, which are irregularly curved and convergent.

_Dimensions._--Cephalis 0.01 to 0.02 long, 0.03 to 0.04 broad; thorax 0.09 to 0.11 long, 0.08 to 0.09 broad.

_Habitat._--Central Pacific, Station 263 to 274, surface, and at various depths.

20. _Carpocanium verecundum_, n. sp. (Pl. 52, figs. 12, 13).

Shell ovate, smooth, with flat, perfectly hidden cephalis (fig. 12). Length of the two joints = 1 : 9, breadth = 4 : 9. Pores subregular, circular, twice as broad as the bars, in about eighteen, {1285}partly interrupted, longitudinal rows, separated by prominent crests. Mouth little constricted. Peristome with twenty to twenty-four broad, lamellar, pointed feet, which are about as long as the shell, little curved, and convergent.

_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.09 long, 0.09 broad.

_Habitat._--North Pacific, Station 244, depth 2900 fathoms.

21. _Carpocanium virgineum_, n. sp. (Pl. 52, fig. 20).

Shell ovate, smooth, with flat perfectly hidden cephalis. Length of the two joints = 1 : 8, breadth = 3 : 9. Pores regular, circular, hexagonally framed, as broad as the bars, in about sixteen longitudinal rows on each side. Mouth little constricted. Peristome with eighteen to twenty-four very large, lamellar, pointed feet, which are longer than the shell, and so curved and convergent that their distal points come nearly in contact.

_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.09 broad.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

Subfamily 2. SETHOPHÆNIDA, Haeckel, 1881, Prodromus, p. 433.

_Definition._--#Anthocyrtida# with the basal mouth of the shell fenestrated (vel Dicyrtida multiradiata clausa).

Genus 570. _Sethophæna_,[187] Haeckel, 1881, Prodromus, p. 433.

_Definition._--#Sethophænida# (vel Dicyrtida multiradiata clausa) with lateral apophyses. Cephalis with a horn.

The genus _Sethophæna_ and the following _Clistophæna_ form together the small subfamily of Sethophænida, comprising those Dicyrtida in which the thorax bears numerous radial appendages (four to six or more), and the mouth is closed by a lattice-plate. In _Sethophæna_ the apophyses are lateral wings, as in _Micromelissa_, from which it may be derived by development of secondary wings, interpolated between the three primary wings.

1. _Sethophæna tetraptera_, n. sp.

Shell smooth, with deep collar stricture. Length of the two joints = 3 : 10, breadth = 4 : 9. Cephalis subspherical, without horn. Thorax ovate, with rounded hemispherical base, and subregular, hexagonal pores. From its upper half (below the collar stricture) arise four divergent, {1286}conical, straight wings, of half the length, opposite in pairs in two meridional planes, perpendicular to one another (compare _Tetralacorys_, Pl. 65, figs. 4, 5).

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.09 broad.

_Habitat._--South Pacific, Station 300, depth 1375 fathoms.

2. _Sethophæna hexaptera_, n. sp. (Pl. 97, fig. 13).

Shell rough, pear-shaped, with distinct collar stricture. Length of the two joints = 1 : 4, breadth = 2 : 4. Cephalis hemispherical, with a conical horn of the same length. Thorax inflate, inversely ovate, nearly pear-shaped, with subregular, circular pores. From its upper half arise, by a broad base, six divergent, strong, conical wings, which are horn-like, curved downwards, and half as long as the thorax.

_Dimensions._--Cephalis 0.025 long, 0.04 broad; thorax 0.09 long, 0.08 broad.

_Habitat._--Central Pacific, Station 268, depth 2900 fathoms.

3. _Sethophæna enneaptera_, n. sp.

Shell rough, with sharp collar stricture. Length of the two joints = 1 : 6, breadth = 1 : 3. Cephalis subspherical, with a stout conical horn of twice the length. Thorax inversely ovate, with pointed, conical, basal part, and irregular, roundish pores. From its middle part arise, by a broad triangular base, nine compressed, divergent wings, which are a little curved, slender, and about as long as the thorax.

_Dimensions._--Cephalis 0.025 long, 0.03 broad; thorax 0.17 long, 0.1 broad.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

4. _Sethophæna polyptera_, n. sp.

Shell thorny, with slight collar stricture. Length of the two joints = 1 : 10, breadth = 3 : 8. Cephalis flat, cap-shaped, without horn. Thorax pear-shaped, with hemispherical base and regular, circular pores. From its lower half (beyond the equator) arises a corona of numerous short conical wings (eighteen to twenty-four), which are a little curved, and divergent downwards, scarcely one-third as long as the thorax.

_Dimensions._--Cephalis 0.015 long, 0.04 broad; thorax 0.15 long, 0.12 broad.

_Habitat._--North Pacific, Station 253, depth 3125 fathoms.

Genus 571. _Clistophæna_,[188] Haeckel, 1881, Prodromus, p. 433.

_Definition._--#Sethophænida# (vel Dicyrtida multiradiata clausa) with terminal apophyses. Cephalis with a horn.

{1287}The genus _Clistophæna_ agrees with the preceding _Sethophæna_ in the mouth of the thorax being closed by a lattice-plate. But the appendages of the thorax are terminal feet, not lateral wings; their number is commonly six or nine, rarely more. _Clistophæna_ may be derived either from _Tetrahedrina_ by interpolation of secondary feet between the three primary, or from _Sethamphora_ by development of a basal lattice-plate closing the mouth.

1. _Clistophæna rüstiana_, n. sp. (Pl. 57, fig. 6).

Shell rough, with distinct collar stricture. Length of the two joints = 3 : 10, breadth = 4 : 11. Cephalis hemispherical, with small, circular pores and a stout oblique horn three times the length, which is three-sided prismatic, and at the top denticulate. Thorax subconical, inflate, with regular, circular, quincuncial pores, increasing in size towards the base. Margin of the flat base, with six divergent, stout feet of the same prismatic form as the cephalic horn, with denticulate distal ends, about as long as the thorax. This elegant species is dedicated to Dr. Rüst of Freiburg, the discoverer of numerous fossil Radiolaria in the Liassic and Jurassic formations.

_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.11 broad.

_Habitat._--Central Pacific, Station 265, depth 2900 fathoms.

2. _Clistophæna hexolena_, n. sp.

Shell smooth, with slight collar stricture. Length of the two joints = 1 : 4, breadth = 1 : 5. Cephalis subspherical, small, with a large, vertical, cylindrical horn, about as long as the shell, and small, circular pores. Thorax nearly three-sided pyramidal or tetrahedral, with three rounded edges and sub-regular, circular pores. Margin of the flat base with six conical, divergent, straight feet, somewhat shorter than the thorax. (Three on the corners, one on the middle of each side of the triangular base.)

_Dimensions._--Cephalis 0.03 diameter, thorax 0.12 long, 0.14 broad.

_Habitat._--North Pacific, Station 241, depth 2300 fathoms.

3. _Clistophæna pyramidalis_, n. sp.

Shell smooth, with slight collar stricture. Length of the two joints = 2 : 8, breadth = 3 : 10. Cephalis hemispherical, with a stout pyramidal horn of twice the length. Thorax six-sided pyramidal, with regular, circular pores of equal size, and six prominent, straight edges, which are prolonged into six divergent, pyramidal feet of half the length.

_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.1 broad.

_Habitat._--Central Pacific, Station 274, depth 2750 fathoms.

{1288}4. _Clistophæna armata_, n. sp. (Pl. 57, fig. 7).

Shell spiny, with deep collar stricture. Length of the two joints = 4 : 18, breadth = 5 : 15. Cephalis subspherical, with small, circular, hexagonally-framed pores, and a stout, three-sided prismatic, cuspidate horn of the same length. Thorax pear-shaped, with regular, circular pores and three pairs of stout pyramidal wings, placed in the three primary meridional planes of the collar beams; three of them lie in the upper, and three in the lower third of the thorax. Margin of the flat base with nine cylindrical, somewhat club-shaped, divergent feet.

_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.18 long, 0.15 broad.

_Habitat._--Central Pacific, Station 266, depth 2750 fathoms.

5. _Clistophæna enneolena_, n. sp.

Shell spiny, with sharp collar stricture. Length of the two joints = 4 : 20, breadth 5 : 16. Cephalis hemispherical, hyaline, with a stout conical horn of the same length and some small accessory horns. Thorax ovate, spiny, with subregular, circular pores. Margin of the vaulted base with nine divergent, conical feet, half as long as the thorax.

_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.2 long, 0.16 broad.

_Habitat._--South Pacific, Station 296, depth 1825 fathoms.

6. _Clistophæna polyolena_, n. sp.

Shell smooth, conical, with obliterated collar stricture. Length of the two joints = 1 : 5, breadth = 2 : 5. Cephalis hemispherical, with small, circular pores and two divergent conical horns (a major occipital and a smaller frontal horn). Thorax obtusely conical, with regular, hexagonal pores at the mantle, and circular pores in the basal plate, the margin of which bears eighteen vertical, parallel, conical feet, as long as the cephalis.

_Dimensions._--Cephalis 0.015 long, 0.025 broad; thorax 0.08 long, 0.08 broad.

_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.

Family LXIV.--#SETHOCYRTIDA#, n. fam.

_Sethocorida et Sethocapsida_, Haeckel, 1881, Prodromus, pp. 439, 433.

_Definition._--#Dicyrtida# eradiata. (#Cyrtoidea# with a two-jointed shell, divided by a transverse constriction into cephalis and thorax, without radial apophyses).

The family #Sethocyrtida#, composed of the Sethocorida and Sethocapsida of my Prodromus, comprises those #Cyrtoidea# in which the shell is two-jointed and bears no radial apophyses. The two subfamilies differ in the shape of the mouth, which in the Sethocorida is a simple wide opening, and in the Sethocapsida is closed by a lattice-plate. The former are here divided into eight, the latter into three genera.

{1289}Numerous living and fossil forms of Sethocyrtida were previously described by Ehrenberg, partly in his genera _Dictyocephalus_ and _Lophophæna_, partly (intermingled with three-jointed and many-jointed forms) in the genera _Eucyrtidium_ and _Lithocampe_. A larger number of new forms has been found in the Radiolarian ooze collected by the Challenger, and others fossil in Barbados. Many of these Sethocyrtida are common and widely distributed. When a new third joint is formed on their basal mouth, they pass over into Theocyrtida.

The cephalis is usually subspherical or hemispherical, and much smaller than the thorax, the form of which exhibits all possible intermediate stages between flat, discoidal, conical, cylindrical, and ovate forms. The wide open mouth becomes more and more constricted, and finally closed in the Sethocapsida. The majority of the Sethocyrtida may have been derived either from the Tripocyrtida, or from the Anthocyrtida by reduction and loss of the radial apophyses.

_Synopsis of the Genera of Sethocyrtida._

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I. Subfamily Sethocorida.
Terminal mouth of the thorax a simple wide opening.
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Thorax conical or campanulate, gradually dilated.
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Shell simple, without mantle, 572. _Sethoconus_.

Shell double, with an arachnoid mantle, 573. _Periarachnium_.
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Thorax discoidal, flatly expanded.
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Cephalis very large, without horn, 574. _Sethocephalus_.

{ Mouth simple, 575. _Sethocyrtis_.
Cephalis with a single horn. {
{ Mouth tubular, 576. _Sethocorys_.
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Thorax cylindrical or ovate, with truncate, constricted or tubular mouth.
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Cephalis with two horns or a bunch of horns, 577. _Lophophæna_.

Cephalis without horn, 578. _Dictyocephalus_.
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II. Subfamily Sethocapsida.
Terminal mouth closed by a lattice-plate.
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Cephalis free, not hidden in the thorax
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One horn, 579. _Sethocapsa_.