Chapter XXVIII: Section IV: STICHOCYRTIDA, Haeckel, 1862, Monogr. d. Radiol., p. 280, 312 (3)

_Dimensions._--Length of the shell (with twelve joints) 0.24; length of each joint 0.02, breadth 0.04.

_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms.

{1483}5. _Artostrobus articulatus_, n. sp. (Pl. 79, fig. 16).

Shell subcylindrical, with elegant longitudinal ribs and five sharp strictures. All six joints nearly equal in length, each with three or four transverse rows of small circular pores. The middle joints twice as broad as long. Cephalis hemispherical with a conical, oblique horn.

_Dimensions._--Length of the shell (with six joints) 0.16, length of a single joint 0.02 to 0.03, breadth 0.04 to 0.05.

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

Genus 646. _Lithomitra_,[263] Bütschli, 1882, Zeitschr. f. wiss. Zool., p. 529.

_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with cylindrical shell, the upper pole of which is rounded, the lower truncate. Cephalis without horn.

The genus _Lithomitra_ differs from the preceding genus _Artostrobus_ in the absence of a cephalic horn, and therefore bears to it the same relation as _Dictyomitra_ does to _Lithostrobus._ In many species the joints are very short, and bear only a single transverse row of pores, and since the constrictions between the joints are often very slight, Lithomitra becomes very similar to the Dicyrtide _Dictyocephalus_.

Subgenus 1. _Lithomitrella_, Haeckel.

_Definition._--A single transverse row of small circular pores on each joint. (Sometimes on the uppermost joints two or three rows.)

1. _Lithomitra pachyderma_, Bütschli.

_Lithomitra pachyderma_, Bütschli, 1882, Zeitschr. f. wiss. Zool., Vol.
xxxvi. p. 529.

_Eucyrtidium pachyderma_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 72, Taf. xi. fig. 21.

_Eucyrtidium imbricatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 72, Taf. xi. fig. 22.

Shell thick-walled, subcylindrical, with longitudinal ribs, slightly dilated in the middle, with ten to twelve subequal joints. On the lower edge of each joint a single row of small circular pores. No external strictures. This and the following species (though separated by Ehrenberg as four different species) may be united.

_Dimensions._--Length of the shell (with ten joints) 0.11; length of each joint 0.01 to 0.012, breadth 0.04.

_Habitat._--Fossil in Barbados.

{1484}2. _Lithomitra acephala_, Bütschli.

_Lithomitra acephala_, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol.
xxxvi. p. 529.

_Eucyrtidium acephalum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 70, Taf. xi. fig. 5.

_Eucyrtidium obstipum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 70, Taf. xi. fig. 17.

Shell nearly cylindrical, smooth, thick-walled, with twelve to sixteen subequal joints. On each joint a single row of small circular pores. No external strictures. Scarcely differing from the preceding species; the joints are broader and shorter, the cephalis is larger (by union of some joints?), and the ribs of the surface less distinct.

_Dimensions._--Length of the shell (with twelve joints) 0.1; length of each joint 0.006 to 0.009, breadth 0.04.

_Habitat._--Fossil in Barbados.

3. _Lithomitra lineata_, Haeckel.

_Lithocampe lineata_, Ehrenberg (partim), 1838, Monatsber. d. k. preuss.
Akad. d. Wiss. Berlin, p. 130; Mikrogeol., 1854, Taf. xxii. fig. 26.

_Lithocampe lineata_, Haeckel, 1862, Monogr. d. Radiol., p. 316.

_Eucyrtidium lineatum_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xxxvi. fig. 16; Abhandl.
d. k. Akad. d. Wiss. Berlin, 1875, p. 72, Taf. xi. fig. 9.

_Dictyomitra lineata_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 101, Taf.
iii. fig. 22.

Shell subcylindrical, smooth, with longitudinal ribs, and four to eight slight transverse strictures. Cephalis small, subspherical, with few small pores. Thorax broader, with two or three transverse rows of pores. Each succeeding (abdominal) joint with a single transverse row of small pores. Variable and nearly related to the two preceding species (compare my Monograph, _loc. cit._).

_Dimensions._--Length of the shell (with six to eight joints) 0.06 to 0.08; length of each joint (on an average) 0.01, breadth 0.03.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, in various depths; many stations; fossil in Secondary and Tertiary rocks of many places.

4. _Lithomitra nodosaria_, n. sp. (Pl. 79, fig. 1).

Shell subcylindrical, with longitudinal ribs, and five to eight transverse strictures, and prominent girdles between them. On each girdle (at the lowermost edge of each joint) a single transverse row of circular pores. The three or four uppermost joints are united, and represent a conical cephalis.

_Dimensions._--Length of the shell (with six joints) 0.1; length of each joint 0.01 to 0.15, breadth 0.04 to 0.06.

_Habitat._--Central Pacific, Station 263 to 274, depth 2350 to 2925 fathoms.

{1485}5. _Lithomitra eruca_, n. sp. (Pl. 79, fig. 3).

Shell subcylindrical, diminishing slightly towards both ends, with ten to fifteen slight strictures. On each joint a single transverse row of circular pores, descending obliquely in the wall. The two or three first joints form together a roundish cephalis. Usually each joint is three times as broad as long.

_Dimensions._--Length of the shell (with twelve joints) 0.2; length of each joint (on an average) 0.016, breadth 0.05.

_Habitat._--Central Pacific, Station 265 to 268, depth 2700 to 2900 fathoms; fossil in Barbados.

6. _Lithomitra chrysalis_, n. sp. (Pl. 79, fig. 4).

Shell subcylindrical, diminishing slightly towards both ends, with elegant longitudinal ribs, and with five to eight slight strictures. Each of the upper joints with two (or sometimes three) transverse rows of small pores; each of the lower joints with only a single row.

_Dimensions._--Length of the shell (with six joints) 0.11; length of each joint 0.01 to 0.015, breadth 0.04 to 0.05.

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

Subgenus 2. _Lithomitrissa_, Haeckel.

_Definition._--All (or the majority) of the joints of the shell with several transverse rows of pores, in variable number.

7. _Lithomitra cylindrica_, n. sp.

Shell cylindrical, smooth, with twelve to sixteen internal septal rings (without external strictures). On each joint two transverse rows of small, regular, circular pores. The hemispherical cephalis also has two rows of pores. Each joint is twice as broad as long.

_Dimensions._--Length of the shell (with sixteen joints) 0.3; length of each joint 0.02, breadth 0.04.

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

8. _Lithomitra costata_, Haeckel.

_Dictyomitra costata_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 101, Taf.
iii. fig. 23.

Shell with longitudinal ribs, in the upper half conical, in the lower half cylindrical, with six to eight slight strictures. Small, circular pores in regular transverse rows; three rows in each upper joint, two rows in each lower joint (the last joints sometimes confluent).

{1486}_Dimensions._--Length of the shell (with eight joints) 0.15; length of each joint 0.017 to 0.023, breadth 0.04 to 0.05.

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

9. _Lithomitra punctata_, Haeckel.

_Lithocampe punctata_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 84.

_Eucyrtidium punctatum_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 24.

_Dictyomitra punctata_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 101, Taf.
iii. fig. 24.

Shell subcylindrical, smooth, with four to six distinct strictures. Cephalis small, subspherical. Thorax campanulate-conical. Abdomen cylindrical, with three to four equal joints. In each joint five to six transverse rows of small, circular pores, quincuncially disposed.

_Dimensions._--Length of the shell (with five joints) 0.1; length of each joint (except the first) 0.02, breadth 0.05.

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

10. _Lithomitra seriolata_, Haeckel.

_Eucyrtidium seriolatum_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 33.

_Lithocampe seriolata_, Haeckel, Monogr. d. Radiol., p. 316.

Shell subcylindrical, smooth, with four to six sharp strictures. Cephalis small, hemispherical. Thorax conical. Abdomen cylindrical, with three to five different joints of alternate sizes. Small circular pores in transverse rows; three or four rows in the third and fifth joints, seven or eight rows in the second, fourth, and sixth joints.

_Dimensions._--Length of the shell (with six joints) 0.1; length of the second and fourth joints 0.03, of the third and fifth joints 0.015.

_Habitat._--Mediterranean, Crete (Ehrenberg), Corfu (Haeckel).

11. _Lithomitra hyperborea_, Haeckel.

_Eucyrtidium hyperboreum_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol.
xxii., pl. i. fig. 10.

_Lithocampe hyperborea_, Haeckel, 1862, Monogr. d. Radiol., p. 315.

Shell cylindrical, with prominent longitudinal ribs and six deep strictures. Cephalis hemispherical. On each joint three to four transverse rows of small, obsolete pores. Each joint is about twice as broad as long.

_Dimensions._--Length of the shell (with six joints) 0.12; length of each joint 0.02, breadth 0.04.

_Habitat._--Arctic and Northern Pacific, Kamtschatka (Bailey).

{1487}12. _Lithomitra australis_, Haeckel.

_Lithocampe australis_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 187.

_Lithocampe australis_, Haeckel, 1862, Monogr. d. Radiol., p. 315.

_Eucyrtidium australe_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xxxv., A 21, fig. 18.

Shell subcylindrical, smooth, with five deep strictures. The two middle joints somewhat larger than the two proximal and the two distal joints. Pores small, circular, in regular, transverse rows; two rows in the first and the sixth joints, five rows in the second and the fifth, seven or eight rows in the third and fourth joints. The two latter are twice as broad as long.

_Dimensions._--Length of the shell (with six joints) 0.14; length of the four smaller joints 0.017, of the two larger joints 0.035; breadth 0.06.

_Habitat._--Antarctic Sea (lat. 78° 10' S., long. 162° W.) Ross.

13. _Lithomitra eminens_, Haeckel.

_Lithocampe eminens_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 102, Taf.
iv. fig. 2.

Shell subcylindrical, rough, with seven slight strictures. The two or three middle joints half as long as the two preceding and the two following joints. Cephalis small, subspherical. Pores small, in subregular, transverse rows, on the fifth and sixth joints only two rows, on the second, third, seventh, and eighth joints four to five rows.

_Dimensions._--Length of the shell (with eight joints) 0.27; length of the fifth and sixth joints 0.17, of the others 0.03 to 0.04; breadth 0.08.

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

14. _Lithomitra infundibulum_, n. sp. (Pl. 79, fig. 5).

Shell in the upper half subconical, in the lower half subcylindrical, rough, with four slight strictures. Cephalis hemispherical. Thorax conical. Abdomen subcylindrical, three-jointed. Pores of the second, third, and fourth joints funnel-shaped, with very small inner, and larger double-contoured outer aperture; on the thorax twelve transverse rows, on the third and fourth joints five rows. Fifth joint with irregular, polygonal pores.

_Dimensions._--Length of the shell (with five joints) 0.2; length of the thorax 0.06, breadth 0.08; length of each abdominal joint 0.04, breadth 0.08.

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

Genus 647. _Eucyrtidium_,[264] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

_Definition_.--#Stichocorida# (vel Stichocyrtida eradiate aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, but not prolonged into a tube. Cephalis with a solid horn.

{1488}The genus _Eucyrtidium_ (as here stated in the definition) and the three following nearly allied genera differ from the preceding Stichocorida in the more or less constricted mouth, and the consequent ovate or spindle-form of the multiarticulate shell. The middle joints of the latter are broader than the upper and the lower joints. In the earlier definition given in my Monograph (1862, pp. 312 to 320), the genus had a much wider sense; but the very large number of species since detected requires a more strict definition. Ehrenberg confounded in his genus _Eucyrtidium_ a large number of very different #Cyrtoidea#. In his last works (1872, 1875) he described not less than one hundred and eleven species, fifty-five fossil and fifty-six living (eight fossil species being yet living). But, in reality, these one hundred and three species belong to twenty or twenty-two very different genera of #Cyrtoidea#.

Subgenus 1. _Eucyrtis_, Haeckel, 1881, Prodromus, p. 438.

_Definition._--All joints of the shell nearly of the same length (excepting often the first). Surface smooth or rough, without spines.

1. _Eucyrtidium acuminatum_, Ehrenberg.

_Eucyrtidium acuminatum_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xii. fig. 27.

_Eucyrtidium acuminatum_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 104,
Taf. iv. fig. 6.

_Eucyrtidium acuminatum_, Haeckel, 1862, Monogr. d. Radiol., p. 326.

_Lithocampe acuminata_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 84.

Shell smooth, slender, nearly spindle-shaped, without external strictures, but with eight to nine internal septal rings. All joints (except the first) nearly of the same length (or the upper somewhat longer). The fifth joint is the broadest. Cephalis small, subspherical, with a short, conical horn. Pores very small and numerous, regular, hexagonal, four to six on the length of each joint.

_Dimensions._--Length of the shell (with eight joints) 0.14; length of each joint about 0.02; greatest breadth, in the fifth joint, 0.07.

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

2. _Eucyrtidium tropezianum_, Haeckel.

_Lithocampe tropeziana_, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 42, Taf. vii. figs. 4, 5, 6.

_Lithocampe tropeziana_, Haeckel, 1862, Monogr. d. Radiol., p. 326.

Shell smooth, slender, nearly spindle-shaped, without external strictures, but with seven or eight internal septal rings. All joints of the same length. The fifth and sixth joints are the broadest. Cephalis hemispherical, with a pyramidal horn of the same length. Pores very small and numerous, regular, circular, hexagonally framed, five to six in the length of each joint. (Very near to the preceding species, but more regular, and with different pores.)

{1489}_Dimensions._--Length of the shell (with eight joints) 0.16, length of each joint 0.02; greatest breadth (in the fifth joint) 0.07.

_Habitat._--Mediterranean, French shore, St. Tropez (J. Müller), surface.

3. _Eucyrtidium hexagonatum_, n. sp. (Pl. 80, fig. 11).

Shell smooth, ovate, with six to seven internal septal rings. All joints (except the first) nearly of the same length; the sixth joint is the broadest. The seventh and eighth joints (broken off in the specimen figured) gradually decrease toward the constricted mouth, which is as broad as the septum between the third and fourth joints. Cephalis and thorax together pear-shaped, with circular pores, sharp lumbar stricture, and a stout, pyramidal horn of the same length. The five or six abdominal joints with regular, hexagonal pores, six or seven in course of the length of each joint.

_Dimensions._--Length of the shell (with eight joints) 0.2, length of each joint 0.025 to 0.03; greatest breadth (in the sixth joint) 0.1.

_Habitat._--Central Pacific, Stations 266 to 272, depth 2425 to 2925 fathoms.

4. _Eucyrtidium fusiforme_, n. sp.

Shell smooth, slender, spindle-shaped, without external strictures, but with ten to twelve internal septal rings. All joints of the same length; the sixth joint is the broadest. Cephalis conical, with a pyramidal horn of the same length. Pores regular, circular, four or five in course of the length of each joint. (Differs from all other species of the genus in the regular, slender, spindle form; the constricted mouth of the last joint is half as broad as the sixth joint.)

_Dimensions._--Length of the shell (with twelve joints) 0.24, length of each joint 0.02; greatest breadth (on the sixth joint) 0.06, of the mouth 0.03.

_Habitat._--Indian Ocean, Maldive Islands (Haeckel, 1882), surface.

5. _Eucyrtidium doliolum_, n. sp.

Shell smooth, barrel-shaped, or nearly spindle-shaped, with eight or nine distinct strictures. All joints (except the first) of the same length; the fourth joint is the broadest. Cephalis small, subspherical, with two short, divergent, conical horns. Pores regular, circular, hexagonally framed, three to four in course of the length of each joint.

_Dimensions._--Length of the shell (with ten joints) 0.2, length of each joint 0.022; greatest breadth (in the fourth joint) 0.08.

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

Subgenus 2. _Stichocyrtis_, Haeckel, 1881, Prodromus, p. 438.

_Definition._--All joints of the shell nearly of the same length (excepting often the first). Surface spiny.

{1490}6. _Eucyrtidium spinosum_, n. sp.

Shell spiny, slender, ovate, without external strictures, but with seven or eight internal septal rings. Conical spines of different lengths are scattered over the whole surface. All joints have nearly the same length; the sixth is the broadest. Cephalis conical, with one large and two or three smaller conical horns. Mouth constricted, half as broad as the shell. Pores irregular, roundish, double-edged, three to four on the length of each joint.

_Dimensions._--Length of the shell (with eight joints) 0.16, length of each joint 0.02; greatest breadth (on the sixth joint) 0.06.

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

7. _Eucyrtidium chrysalidium_, n. sp.

Shell spiny, spindle-shaped, with four to five slight strictures, above each stricture a circle or girdle of conical spines (as in the similar _Cyrtophormis cingulata_, Pl. 78, fig. 18). All joints (except the first) have the same length. Cephalis subspherical, with a bunch of divergent spines. Mouth constricted, only one-third as broad as the third joint, which is the broadest. Pores subregular, circular, four to five on the length of each joint.

_Dimensions._--Length of the shell (with six joints) 0.18, length of each joint 0.032; greatest breadth 0.08.

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

Subgenus 3. _Artocyrtis_, Haeckel.

_Definition._--Joints of the shell of very different lengths. Surface smooth or rough, without spines.

8. _Eucyrtidium profundissimum_, Ehrenberg.

_Eucyrtidium profundissimum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d.
Wiss. Berlin, p. 293, Taf. vii. fig. 12.

Shell smooth, campanulate, ovate, with three internal septal rings. Four joints of different lengths. Cephalis subspherical, with a small bristle-shaped horn. Thorax campanulate, nearly twice as long as each of the two following joints, which are nearly equal in breadth. Terminal mouth wide open, little constricted. Pores very small and numerous, regular, hexagonal.

_Dimensions._--Length of the shell (with four joints) 0.12; length of the thorax 0.05, breadth 0.07.

_Habitat._--Pacific; many Stations (Stations 206, 225, 253, 265, &c.), in depths between 2000 and 4000 fathoms.

{1491}9. _Eucyrtidium anthophorum_, Haeckel.

_Thyrsocyrtis anthophora_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 84, Taf. xii. fig. 9.

Shell smooth, slender, ovate, with three slight strictures. Four joints of different lengths. Cephalis subspherical, with a stout, club-shaped, spinulate or branched horn of the same length. Second campanulate and third subcylindrical joint about equal in size. Fourth joint only half as long, with slightly constricted mouth (broken off in Ehrenberg's figure). Pores small and numerous, regular, circular, quincuncial.

_Dimensions._--Length of the shell (with four joints) 0.12; length of the second and of the third joints 0.04, breadth 0.05 to 0.06.

_Habitat._--Fossil in Barbados.

10. _Eucyrtidium hertwigii_, n. sp. (Pl. 80, fig. 12).

Shell smooth, ovate, truncate, with three distinct strictures. Four joints of different lengths. Cephalis campanulate, with an internal rod-cross, and a stout pyramidal horn of the same length. Second joint campanulate. Third joint larger, subcylindrical, with a variable number of irregular, longitudinal ribs, some of which are prolonged into the second and fourth joints. The latter is only half as long, and slightly constricted towards the mouth. Pores small and numerous, subregular, circular.

_Dimensions._--Length of the shell (with four joints) 0.22. Length of the single joints, _a_ 0.03, _b_ 0.06, _c_ 0.08, _d_ 0.05; breadth, _a_ 0.03, _b_ 0.1, _c_ 0.12, _d_ 0.11.

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

11. _Eucyrtidium lagena_, Haeckel.

_Eucyrtidium lagena_, Haeckel, 1862, Monogr. d. Radiol., p. 325, Taf. iv.
fig. 11.

_Lithocampe lagena_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 839.

Shell smooth, bottle-shaped, with three distinct strictures. Four joints of different sizes. Cephalis small, spherical, with a bristle-shaped horn of the same length. Second joint conical, third subcylindrical, fourth inflated, with slightly constricted mouth; their lengths about equal. Pores subregular, hexagonal, large, with thin bars.

_Dimensions._--Length of the shell (with four joints) 0.16; length of each of the three lower joints about 0.05, breadth 0.05 to 0.064.

_Habitat._--Mediterranean (Messina).

12. _Eucyrtidium teuscheri_, n. sp. (Pl. 77, fig. 5).

Shell smooth, bottle-shaped, with three distinct strictures. Four joints of different lengths. The third joint four times as long as each of the two first joints, and longer than the fourth, which {1492}is little constricted towards the mouth. The greatest breadth is in the middle of the shell. Cephalis hemispherical, with a small, conical horn of the same length. Pores large, circular, of variable sizes. Dedicated to Dr. Reinhold Teuscher.

_Dimensions._--Length of the shell (with four joints) 0.16. Length of the single joints, _a_ 0.015, _b_ 0.02, _c_ 0.07, _d_ 0.055; breadth, _a_ 0.03, _b_ 0.05, _c_ 0.08, _d_ 0.06.

_Habitat._--Central Pacific, Stations 266 to 274, depth 2350 to 2925 fathoms.

13. _Eucyrtidium bütschlii_, n. sp. (Pl. 77, fig. 7).

Shell rough, slender, ovate, truncate, with three distinct strictures. Four joints of different lengths; the third is the largest, inflated, subspherical. Fourth joint subcylindrical, little constricted towards the truncate mouth. Cephalis hemispherical, with a small, conical horn. Pores circular, much larger in the third joint than in the three others.

_Dimensions._--Length of the shell (with four joints) 0.16. Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.06, _d_ 0.05; breadth, _a_ 0.03, _b_ 0.07, _c_ 0.09, _d_ 0.07.

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

14. _Eucyrtidium galatheæ_, Ehrenberg.

_Eucyrtidium galatheæ_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 242.

Shell smooth, campanulate, with three deep strictures. Four joints of different lengths; the fourth joint is the broadest, twice as long as the third and the second, three times as long as the hemispherical cephalis, which bears a stout, pyramidal, oblique horn of twice the length. Mouth little constricted. Pores regular, circular, in transverse rows, three rows in each of the three first joints, five or six rows in the last joint.

_Dimensions._--Length of the shell (with four joints) 0.12; length of the fourth joint 0.05, breadth 0.07.

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

15. _Eucyrtidium galea_, Haeckel.

_Eucyrtidium galea_, Haeckel, 1862, Monogr. d. Radiol., p. 324, Taf. vii.
figs. 8-10.

_Lithocampe galea_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 838.

Shell smooth, helmet-shaped, with four sharp strictures. Five joints of different lengths. Cephalis small, spherical, with a thin pyramidal horn of the same length. Second joint conical, about as long as the third, longer than the fourth and the fifth joints. The third joint is the broadest. Pores regular, circular, small and numerous.

_Dimensions._--Length of the shell (with five joints) 0.18; length of the second and the third joints 0.05, of the fourth 0.03; breadth 0.08 to 0.1.

_Habitat._--Mediterranean (Messina), surface.

{1493}16. _Eucyrtidium eruca_, Ehrenberg.

_Eucyrtidium eruca_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 70, Taf. x. fig. 13.

Shell smooth, slender, ovate, or nearly spindle-shaped, with four sharp strictures. Five joints of different lengths, the third and fourth nearly equal, twice as long as the fifth, one and a half times as long as the second; the fourth joint is the broadest. Mouth little constricted. Cephalis subspherical, with a small, conical horn. Pores small and numerous, subregular, circular.

_Dimensions._--Length of the shell (with five joints) 0.12 to 0.14; length of the third and the fourth joints, 0.03 to 0.04, breadth 0.04 to 0.05.

_Habitat._--Cosmopolitan; Atlantic, Pacific, in different depths; also fossil in Barbados and Sicily.

17. _Eucyrtidium montiparum_, Ehrenberg.

_Eucyrtidium montiparum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 72, Taf. ix. fig. 11.

Shell rough, nearly spindle-shaped, with five deep strictures. Six joints of different lengths, the third and fourth nearly equal, longer than the fifth and the sixth joints; the fourth joint is the broadest. Mouth slightly constricted. Cephalis very small, hemispherical, hyaline, with a short, conical horn. Pores subregular, circular, twice as broad as in the similar smaller preceding species.

_Dimensions._--Length of the shell (with six joints) 0.2; length of the third and the fourth joints 0.05, breadth 0.07 to 0.08.

_Habitat._--Fossil in Barbados.

18. _Eucyrtidium cienkowskii_, n. sp. (Pl. 80, fig. 9).

Shell smooth, subconical, with five distinct strictures. Six joints of different lengths; the third joint conical, one and a half to two times as long as each of the other joints; the fifth joint is the broadest. Mouth wide, very slightly constricted. Cephalis hemispherical, with an oblique pyramidal horn of the same length. Pores regular, circular, in dense transverse rows; five to six rows in each of the three last joints, eight to nine rows in the third joint.

_Dimensions._--Length of the shell (with six joints) 0.16, length of the third joint 0.04, of each following joint 0.02; greatest breadth (in the fifth joint) 0.08.

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

19. _Eucyrtidium elongatum_, Stöhr.

_Eucyrtidium elongatum_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 105,
Taf. iv. fig. 10.

Shell rough, slender, nearly spindle-shaped, variable in size and form, with six to seven distinct strictures. Seven to eight joints of different lengths, often alternately longer and shorter. The second {1494}and the last joints are the longest, the third is the broadest. Mouth slightly constricted (broken off in Stöhr's figure). Cephalis small, subspherical, with a small, oblique, curved horn. Pores irregular.

_Dimensions._--Length of the shell (with seven joints) 0.2; length of the single joints, between 0.02 and 0.04, breadth 0.06 to 0.08.

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

20. _Eucyrtidium stöhrii_, n. sp.

Shell smooth, spindle-shaped, gradually diminishing towards both ends, with eight to ten distinct strictures. Nine to eleven joints of different lengths; the two or three middle joints--fifth, sixth, and seventh--longer and broader than the other joints; the broadest is the fifth joint, which is twice to three times as long as the first and last joints. Cephalis subspherical, with a conical horn of the same length. Terminal mouth strongly constricted, one-half or one-third as broad as the fifth joint. Pores small, regular, circular.

_Dimensions._--Length of the shell (with ten joints) 0.22; length of the largest (fifth joint) 0.03, breadth 0.09.

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

21. _Eucyrtidium scalarium_, n. sp.

Shell smooth, slender, ovate, with nine to ten deep strictures, and ten to eleven separate step-like joints of different lengths. The sixth joint is the longest, twice as long as the fourth, and three times as long as the third and the last joint; the seventh and eighth joints are the broadest, one and a half times as broad as the wide mouth. Cephalis hemispherical, with a short pyramidal horn of the same length. Pores small and numerous, subregular, square, in regular transverse rows; six rows in the sixth joint, three rows in the last joint. (Somewhat similar to _Spirocyrtis scalaris_, Pl. 76, fig. 14, but ovate, not conical and not spiral.)

_Dimensions._--Length of the shell (with eleven joints) 0.22, breadth 0.11; length of the last joint 0.01, of the sixth 0.03.

_Habitat._--North Atlantic, Station 64, surface.

Subgenus 4. _Acanthocyrtis_, Haeckel, 1881, Prodromus, p. 437.

_Definition._--Joints of the shell of very different lengths. Surface spiny.

22. _Eucyrtidium tricinctum_, n. sp. (Pl. 78, fig. 13).

Shell spiny, spindle-shaped, with three distinct strictures. Four joints of different lengths, the first and third half as long as the second and fourth; the third joint is the broadest, four times as {1495}broad as the strongly constricted mouth. Spines irregularly scattered over the lower half of the shell, increasing in size towards the mouth. Pores subregular, circular.

_Dimensions._--Length of the shell (with four joints) 0.25. Length of the single joints, _a_ 0.03, _b_ 0.08, _c_ 0.04, _d_ 0.09; breadth (of the third joint) 0.1.

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

23. _Eucyrtidium armatum_, n. sp. (Pl. 78, fig. 14).

Shell spiny, spindle-shaped, with three distinct strictures. Four joints of different lengths, the second and third joints of the same length, shorter than the fourth joint; the third joint is the broadest, four times as broad as the strongly constricted mouth. The latter, as well as the conical cephalis, is armed with an irregular bunch of strong conical spines, while numerous smaller spines are scattered over the whole surface. Pores irregular, roundish, double-contoured.

_Dimensions._--Length of the shell (with four joints) 0.2. Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.05, _d_ 0.08; breadth (of the third joint) 0.1.

_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms.

24. _Eucyrtidium conostoma_, n. sp. (Pl. 78, fig. 16).

Shell spiny, spindle-shaped, with four distinct strictures. Five joints of different lengths, having the proportion = 1 : 2 : 3 : 6 : 10. The fourth joint is the broadest, inflated, twice as broad as long. Cephalis small, with a conical horn of the same length. Fifth joint inversely conical, with a narrow mouth, broader than the cephalis. Short conical spines are scattered over the whole surface. Pores subregular, circular.

_Dimensions._--Length of the shell (with five joints) 0.22. Length of the single joints, _a_ 0.01, _b_ 0.02, _c_ 0.03, _d_ 0.06, _e_ 0.1; breadth (of the fourth joint) 0.09.

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

25. _Eucyrtidium ehrenbergii_, n. sp. (Pl. 78, fig. 15).

Shell spiny, spindle-shaped, with four distinct strictures (the first and the fourth are by a mistake not distinctly figured). Five joints of different lengths, having the proportion = 2 : 3 : 4 : 2 : 5. The third joint is the broadest, twice as broad as long, and twice as broad as the constricted mouth. Whole surface covered with strong spines. Pores irregular, roundish.

_Dimensions._--Length of the shell (with five joints) 0.16. Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.02, _e_ 0.05; breadth (in the third joint) 0.08.

_Habitat._--Western Tropical Pacific, Station 220, depth 1100 fathoms.

26. _Eucyrtidium ovatum_, n. sp.

Shell spiny, inversely ovate, with five sharp strictures. Six joints of different lengths, having the proportion = 1 : 3 : 2 : 1 : 1 : 3. The third joint is the broadest, three times as broad as the {1496}constricted mouth. Cephalis with a stout pyramidal horn of the same length. Whole surface spiny. Pores irregular, roundish.

_Dimensions._--Length of the shell (with six joints) 0.22. Length of the single joints, _a_ 0.02, _b_ 0.06, _c_ 0.04, _d_ 0.02, _e_ 0.02, _f_ 0.06; breadth (in the third joint) 0.11.

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

Genus 648. _Eusyringium_,[265] Haeckel, 1881, Prodromus, p. 437.

_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, and prolonged into a terminal cylindrical tube. Cephalis with a solid horn.

The genus _Eusyringium_ differs from the preceding closely allied genus _Eucyrtidium_ in the peculiar formation of the last shell-joint, representing a narrow, cylindrical, fenestrated tube. It exhibits, therefore, to the latter the same relation as _Theosyringium_ bears to _Theocorys_.

Subgenus 1. _Eusyringartus_, Haeckel.

_Definition._--Shell with three strictures and four joints; the third joint is the largest, inflated, and much broader than the three others.

1. _Eusyringium conosiphon_, n. sp. (Pl. 78, fig. 10).

Shell with four joints, very thick-walled, rough. Cephalis hemispherical, with a very stout, smooth, three-sided pyramidal horn of the same length and breadth. Thorax hemispherical. Third joint subspherical, three times as long, and twice as broad as the thorax, and of the same length as the slender, inversely conical fourth joint. Pores in the three first joints subregular, circular, in the fourth joint irregular.

_Dimensions._--Length of the shell (with four joints) 0.25. Length of the single joint _a_ 0.02, _b_ 0.03, _c_ 0.1, _d_ 0.1; breadth 0.12.

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

2. _Eusyringium pachysiphon_, n. sp. (Pl. 78, fig. 11).

Shell with four joints, very thick-walled, rough. Cephalis conical, with a thick, dimpled, conical horn of the same length. Thorax hemispherical. Third joint inflated, subspherical, and fourth joint slender, inversely conical, as in the similar preceding species. Differs from the latter {1497}mainly in the form of the cephalic horn, and the cylindrical tube of the last joint. Pores subregular, circular.

_Dimensions._--Length of the shell (with four joints) 0.3. Length of the single joints, _a_ 0.03, _b_ 0.03, _c_ 0.12, _d_ 0.12; breadth 0.15.

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

3. _Eusyringium macrosiphon_, n. sp. (Pl. 78, fig. 12).

Shell with four joints, thick-walled, rough. Cephalis subspherical with a large, dimpled, conical horn of twice the length. The three following joints nearly of the same shape as in the two similar preceding species. It differs from these in the smaller size, the larger cephalic horn, and the longer tube of the fourth joint, which is twice as long as the subspherical third joint (in the figure the lower half is broken off). Pores subregular, circular.

_Dimensions._--Length of the shell (with four joints) 0.3. Length of the single joints, _a_ 0.03, _b_ 0.03, _c_ 0.08, _d_ 0.16; breadth 0.09.

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

4. _Eusyringium leptosiphon_, n. sp.

Shell with four joints, thin-walled, smooth. Cephalis subspherical, with a large, dimpled, slender, conical horn of three times the length. Thorax hemispherical. Third joint ovate, four times as long as the thorax, and of the same length as the thin, cylindrical tube of the fourth joint. Differs from the three preceding species in the more slender form and the thinness of the tube. Pores irregular, roundish.

_Dimensions._--Length of the shell (with four joints) 0.33. Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.13, _d_ 0.15; breadth 0.1.

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

5. _Eusyringium sipho_, Haeckel.

_Eucyrtidium sipho_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 72, Taf. ix. fig. 2.

Shell with four joints, thick-walled, smooth. Cephalis subspherical, hyaline, without pores, with a thick, conical horn of twice the length. Thorax hemispherical. Third joint ovate, four times as long as the thorax, and of the same length as the thin, cylindrical fourth joint. Pores subregular, circular, in the fourth joint twice as broad as in the third, and three times as broad as in the second joint.

_Dimensions._--Length of the shell (with four joints) 0.22. Length of the single joints, _a_ 0.02, _b_ 0.02, _c_ 0.09, _d_ 0.09; breadth 0.08.

_Habitat._--Fossil in Barbados.

{1498}6. _Eusyringium fistuligerum_, Haeckel.

_Eucyrtidium fistuligerum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d.
Wiss. Berlin, p. 70, Taf ix. fig. 3.

Shell with four joints, thin-walled, smooth. Cephalis subspherical, with numerous very small pores, and a stout, pyramidal horn of the same length. Thorax hemispherical. Third joint subspherical, four times as long as the thorax, and of the same length as the slender, inversely conical or cylindrical, fourth joint. Pores irregular, roundish or circular, in the fourth joint twice as broad as in the two preceding joints.

_Dimensions._--Length of the shell (with four joints) 0.2. Length of the single joints, _a_ 0.02, _b_ 0.02, _c_ 0.08, _d_ 0.08; breadth 0.09.

_Habitat._--Fossil in Barbados.

Subgenus 2. _Eusyringoma_, Haeckel.

_Definition._--Shell with four or more strictures, and five or more joints; the last joint is strongly constricted, and forms a narrow cylindrical tube.

7. _Eusyringium lagenoides_, Haeckel.

_Eucyrtidium lagenoides_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 104,
Taf. iv. fig. 8.

Shell with five joints, and four sharp strictures, nearly spindle-shaped. The third joint is twice as long as the second and the fourth. Cephalis small, cap-shaped, with a thin conical horn of the same length. The fifth joint is in Stöhr's figure broken off, but well conserved in a specimen from Caltanisetta, and represents a slender cylindrical tube, with few pores, half as long as the shell. Pores small, subregular, circular, quincuncial.

_Dimensions._--Length of the shell (with five joints) 0.24, breadth 0.08; length of the third joint 0.06, of the second and the fourth 0.03, of the fifth 0.1; breadth of the basal tube 0.027.

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

8. _Eusyringium rhaphanus_, Haeckel.

_Eucyrtidium rhaphanus_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 106,
Taf. iv. fig. 12.

Shell with six or seven joints of very different lengths, in the upper half campanulate, in the lower cylindrical. The second and the two last joints are the longest. Cephalis small, subspherical, with a short conical horn. The last joint is a narrow cylindrical tube of variable length, scarcely one-fourth as broad as the preceding joints. Pores in the upper joints regular, circular, in the lower irregular, roundish.

_Dimensions._--Length of the shell (with seven joints) 0.2, breadth 0.1; length of the second and last joints 0.03 to 0.04; breadth of the basal tube 0.025.

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

{1499}9. _Eusyringium siphonostoma_, n. sp. (Pl. 80, fig. 14).

Shell with eight joints, in the upper half slender, conical, in the lower half cylindrical. The single joints are separated by seven internal annular septa. The third and the seventh joints are the largest, twice as long as the three intercalated joints. Cephalis small, cap-shaped, with a conical horn of twice the length. The last joint (broken off in the specimen figured) is a narrow cylindrical tube, one-third as long and one-third as broad as the shell. Pores regular, circular, quincuncial.

_Dimensions._--Length of the shell (with eight joints) 0.24, breadth 0.08; length of the single joints 0.02 to 0.04; breadth of the basal tube 0.03.

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

10. _Eusyringium cannostoma_, n. sp. (Pl. 80, fig. 13).

Shell with nine or ten joints, slender ovate. The single joints are separated by eight or nine internal annular septa. The third joint is the longest, about twice or three times as long as each following joint. Cephalis hemispherical, with a curved, conical horn of the same length. The last joint is a narrow, cylindrical tube, about as long as the third joint, but only one-fourth as broad. Pores small, regular, circular, quincuncially disposed, and hexagonally framed.

_Dimensions._--Length of the shell (with ten joints) 0.22, breadth 0.08; length of the third joint 0.04, of the other joints 0.01 to 0.02, of the basal tube 0.04; breadth of the latter 0.02.

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

Genus 649. _Siphocampe_,[266] Haeckel, 1881, Prodromus, p. 438.

_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, but not prolonged into a tube. Cephalis with an oblique, open, apical tube.

The genus _Siphocampe_ differs from the closely allied genera _Lithocampe_ and _Eucyrtidium_ in a very remarkable character, viz., the development of a hollow cylindrical tube on the cephalis. This probably serves for the emission of a bunch of pseudopodia. It has the same position and the same oblique direction on the cephalis as the solid apical horn of _Eucyrtidium_.

Subgenus 1. _Siphocampula_, Haeckel.

_Definition._--All joints of the shell (excepting the first) are nearly equal in length.

{1500}1. _Siphocampe tubulosa_, n. sp. (Pl. 79, fig. 13).

Shell slender nearly spindle-shaped, with eight deep transverse strictures, and elegant longitudinal ribs. Nine joints slightly different in length and shape. Cephalis flat, cap-shaped, with three or four transverse rows of small pores, and a cylindrical, oblique tubule of twice the length. Each successive joint with a single transverse row of regular, circular pores at its lower edge, separated by divergent, longitudinal ribs. Last joint shorter, with a hyaline annular peristome of the same length. Mouth half as broad as the middle part of the shell.

_Dimensions._--Length of the shell (with nine joints) 0.24; length of each joint (on an average) 0.02 to 0.03; breadth 0.08.

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

2. _Siphocampe annulosa_, n. sp. (Pl. 79, fig. 10).

Shell slender, subcylindrical, with nine slight transverse strictures, and interrupted longitudinal ribs. Ten joints nearly equal in length and shape, excepting the two first, which together form a hemispherical cephalothorax, with six to eight transverse rows of pores. Tubule of the cephalis short and wide, truncate, conical. Each of the eight abdominal joints with a single transverse row of small pores. Mouth constricted, without tubulose peristome, half as broad as the shell.

_Dimensions._--Length of the shell (with ten joints) 0.18; length of each joint (on an average) 0.02, breadth 0.07.

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

3. _Siphocampe caminosa_, n. sp. (Pl. 79, fig. 12).

Shell slender, subcylindrical, with six deep transverse strictures. Seven joints nearly equal in length and breadth. Cephalis hemispherical, with an oblique, cylindrical tubule of twice the length (in the figure the greater part is broken away). Small circular pores in transverse rows and in variable number; usually three rows in the first and the last joint, five rows in the fourth joint, four rows in each of the other joints. Mouth constricted, with a short tubulose peristome, only one-third as broad as the shell.

_Dimensions._--Length of the shell (with seven joints) 0.18; length of each joint (on an average) 0.025, breadth 0.055.

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

4. _Siphocampe erucosa_, n. sp. (Pl. 79, fig. 11).

Shell slender, nearly spindle-shaped, with five slight transverse strictures. Six joints nearly equal in length. The two first joints are united, and form together a hemispherical cephalothorax, with a short, oblique, cylindrical tubule. Pores regular, circular, double-contoured, in regular, transverse rows; two rows in the first and the last joints, four rows in each of the four middle joints. Mouth constricted, without peristome, only one-third as broad as the shell.

{1501}_Dimensions._--Length of the shell (with six joints) 0.14; length of each joint (on an average) 0.02, breadth 0.07.

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

Subgenus 2. _Siphocampium_, Haeckel, 1881, Prodromus, p. 437.

_Definition._--The joints of the shell are very different in length.

5. _Siphocampe quadrantalis_, n. sp.

Shell nearly spindle-shaped, with three deep strictures. Four joints of very different lengths. Cephalis subspherical with an oblique cylindrical tubule of twice the length, and with few small pores. Thorax ovate, half as long as the shell, with twelve transverse rows of small pores. Abdomen with two short joints, each of which has two transverse rows of pores. Mouth constricted, one-third as broad as the thorax.

_Dimensions._--Length of the shell (with four joints) 0.18; length of the thorax 0.1, breadth 0.08.

_Habitat._--Western Tropical Pacific; North Coast of New Guinea, Station 220, depth 1100 fathoms.

6. _Siphocampe spiralis_, n. sp. (Pl. 79, fig. 14).

Shell nearly spindle-shaped, with eight slight strictures. Nine joints of very different lengths. Cephalis subspherical, with an oblique cylindrical tubule of the same length, and numerous small pores. Thorax conical, one-fourth as long as the shell, with eight transverse rows of small pores. Abdomen with numerous prominent, spirally convoluted ribs, and spiral rows of pores between them. The first abdominal joint is from two to three times as long as each of the six following joints. Abdominal pores larger, roundish, disposed in eleven transverse rows. Four rows in the first abdominal joint, one row in each of the five following, and two rows in the last joint. Mouth slightly constricted, two-thirds as broad as the shell.

_Dimensions._--Length of the shell (with nine joints) 0.17, cephalis 0.02, thorax 0.04, abdomen 0.11; breadth 0.06.

_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms; also fossil in Barbados.

Genus 650. _Lithocampe_,[267] Ehrenberg, 1838, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 128 (_sensu emendato_).

_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, but not prolonged into a tube. Cephalis without horn and tube.

{1502}The genus _Lithocampe_ is the oldest of all "Polycystina," being founded by Ehrenberg in 1838 upon _Lithocampe radicula_. Afterwards numerous other species, which belong to very different genera, were described by him. In 1862 I attempted to give a more strict definition of this genus in my Monograph (p. 312 to 315), and separated it from the closely allied and often confounded _Eucyrtidium_ by the absence of a cephalic horn. The great number of species afterwards discovered leads to the stricter definition given above.

Subgenus 1. _Lithocampula_, Haeckel.

_Definition._--All joints of the shell (except often the first) are equal or nearly equal in length.

1. _Lithocampe eupora_, Haeckel.

_Eucyrtidium euporum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 291, Taf. iv. fig. 30.

Shell smooth, ovate or subconical, with three deep strictures. Four joints equal in length, gradually increasing in breadth, each with three transverse rows of regular, circular, hexagonally-framed pores; the fourth joint is the broadest. Mouth little constricted, of the same breadth as the third joint.

_Dimensions._--Length of the shell (with four joints) 0.08; length of each joint 0.02, greatest breadth 0.06.

_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; North Atlantic, depth 3600 fathoms (Morse).

2. _Lithocampe platycephala_, Haeckel.

_Eucyrtidium platycephalum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d.
Wiss. Berlin, pp. 145, 293, Taf. iii. fig. 16.

Shell smooth, subconical or slenderly ovate, with three slight strictures. Four joints equal in length, slightly increasing in breadth towards the mouth. The hemispherical cephalis with longitudinal ribs and irregular pores, each of the three other joints with four transverse rows of regular, circular pores. Mouth strongly constricted, half as broad as the third and fourth joints.

_Dimensions._--Length of the shell (with four joints) 0.12; length of each joint 0.03, greatest breadth 0.06.

_Habitat._--North Atlantic, depth 3600 fathoms (Morse).

3. _Lithocampe nereidum_, Haeckel.

_Lithocampe nereidum_, Haeckel, 1862, Monogr. d. Radiol., p. 319.

_Eucyrtidium nereidum_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 242; Mikrogeol., Taf. xxxv. B, _b_, fig. 22.

Shell smooth, slenderly ovate, with four deep strictures. Five joints equal in length, the fourth being the broadest. Each joint with three transverse rows of small, regular, circular pores {1503}(sometimes in the fourth joint there are four rows). Mouth constricted, half as broad as the fourth joint. (In Ehrenberg's figure all five joints are delineated, but the greater part of the hemispherical cephalis is broken off.)

_Dimensions._--Length of the shell (with five joints) 0.1, of each joint 0.02; breadth of the fourth joint 0.05.

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

4. _Lithocampe radicula_, Ehrenberg.

_Lithocampe radicula_, Ehrenberg, 1838, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 130, Taf. iv. fig. 11.; Mikrogeol., 1854, Taf. xxii. fig.
23_a_.

Shell smooth, spindle-shaped, with five sharp strictures. Six joints equal in length, each with four transverse rows of regular, circular, double-edged pores. The third and fourth joints are the broadest, and equal. The constricted mouth is not broader than the hemispherical cephalis, scarcely one-fourth as broad as the third and the fourth joints. This remarkable species is the oldest known skeleton of a Radiolarian, a figure of it being given in 1838, _loc. cit._ (compare my Monograph, 1862, p. 3, 4, 331). But this figure of Ehrenberg is not quite accurate, and differs from other figures of the same species, which he afterwards (1854) published in his Mikrogeologie (_loc. cit._). The best of these is fig. 23_a_ in pl. xxii., and is identical with the typical form (common in Barbados), and according to this I have here framed my description. The sixth joint possesses a distinct (though small) terminal mouth; when this becomes closed, the species passes over into _Stichocapsa radicula_.

_Dimensions._--Length of the shell (with six joints) 0.18, length of each joint (on an average) 0.03; breadth of the third and fourth joints 0.08, of the second and fifth 0.06, of the terminal mouth and the cephalis 0.03.

_Habitat._--Fossil in Tertiary rocks of Barbados.

5. _Lithocampe ventricosa_, Haeckel.

_Dictyomitra ventricosa_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 102,
Taf. iii. fig. 25.

Shell ovate, with six slight strictures. Seven joints nearly equal in length, each with four (or sometimes three or five) transverse rows of small, regular, circular pores, in the last joint the pores are larger. The fourth and fifth joints are the broadest, and are twice as broad as the constricted mouth.

_Dimensions._--Length of the shell (with seven joints) 0.13 to 0.14; length of each joint 0.017 to 0.02, greatest breadth 0.083, mouth 0.04.

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

6. _Lithocampe fusiformis_, n. sp.

Shell smooth, spindle-shaped, decreasing uniformly towards the two blunt poles, with eight or nine sharp strictures, and nine or ten joints of equal lengths, each with four transverse rows of regular, {1504}hexagonal pores. The fourth and fifth joints are the broadest. The constricted mouth is twice as broad as the hemispherical cephalis, half as broad as the fourth joint.

_Dimensions._ --Length of the shell (with ten joints) 0.2, of each joint 0.02; breadth of the fourth joint 0.06, mouth 0.03.

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

Subgenus 2. _Lithocampium_, Haeckel, 1881, Prodromus, p. 437.

_Definition._--The joints of the shell are very different in length.

7. _Lithocampe ovata_, n. sp. (Pl. 77, fig. 1).

Shell smooth, urceolate or ovate, with three sharp strictures. Four joints of different lengths, having the proportion 1 : 2 : 2 : 6. The fourth joint is inflated and the broadest. The mouth is constricted, short, tubular, of the same breadth as the hemispherical cephalis. Pores small, circular, in regular transverse rows; four rows in the first, four in the second, two in the third, and five in the fourth joint. The middle stricture is crossed by longitudinal ribs.

_Dimensions._--Length of the shell (with four joints) 0.11. Length of the single joints, _a_ 0.01, _b_ 0.02, _c_ 0.02, _d_ 0.06; greatest breadth 0.055.

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

8. _Lithocampe aquilonaris_, Haeckel.

_Lithocampe aquilonaris_, Haeckel, 1862, Monogr. d. Radiol., p. 317.

_Eucyrtidium aquilonare_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol.
xxii. p. 4, pl. i. fig. 9.

Shell smooth, subconical, with three distinct strictures. Four joints of different lengths, having the proportion 3 : 1 : 3 : 4. The fourth joint is the broadest, suddenly constricted, with a short tubular mouth of half the breadth. Pores subregular, circular, in transverse rows; three rows in the first joint, two in the second, four in the third, and three in the fourth joint.

_Dimensions._--Length of the shell (with four joints) 0.11. Length of the single joints, _a_ 0.03, _b_ 0.01, _c_ 0.03, _d_ 0.04; breadth 0.06.

_Habitat._--North Pacific, Kamtschatka (Bailey), Station 241, depth 2300 fathoms.

9. _Lithocampe quadrarticulata_, Haeckel.

_Lithocampe quadrarticulata_, Haeckel, 1862, Monogr. d. Radiol., p. 319.

_Eucyrtidium quadrarticulatum_, Ehrenberg, 1861, Monatsber. d. k. preuss.
Akad. d. Wiss. Berlin, p. 299.

Shell smooth, spindle-shaped, with three deep strictures. Four joints of different lengths = 1 : 3 : 4 : 3. The third joint is the broadest, being twice as broad as the constricted mouth of the fourth joint. Pores small, regular, circular, in transverse rows; two being in the first, three in the second, four in the third, three in the fourth joint.

{1505}_Dimensions._--Length of the shell (with four joints) 0.11. Length of the single joints, _a_ 0.015, _b_ 0.03, _c_ 0.04, _d_ 0.025; greatest breadth 0.05.

_Habitat._--North Atlantic (Greenland, depth 1600 fathoms, Ehrenberg), Station 64, surface.

10. _Lithocampe multiseriata_, Haeckel.

_Eucyrtidium multiseriatum_, Ehrenberg, 1872, Monatsber. d. k. preuss.
Akad. d. Wiss. Berlin, page 293, Taf. vii. fig. 9.

Shell smooth, spindle-shaped, or slenderly ovate, with three sharp strictures. Four joints of different lengths = 3 : 4 : 5 : 10. The third and fourth joints nearly equal in breadth, and twice as broad as the hemispherical cephalis. The truncate mouth is slightly constricted. Pores very small and numerous, in regular transverse rows. Three or four rows in the first, five or six in the second, seven or eight in the third, and fifteen to twenty in the fourth joint.

_Dimensions._--Length of the shell (with four joints) 0.11. Length of the single joints, _a_ 0.015, _b_ 0.02, _c_ 0.025, _d_ 0.05; breadth 0.045.

_Habitat._--Tropical Pacific (Philippine Sea, Ehrenberg), Stations 206, 224, 266, in various depths.

11. _Lithocampe diploconus_, n. sp. (Pl. 77, fig. 3).

Shell rough, doubly conical, with three distinct strictures. Four joints of different lengths = 2 : 5 : 5 : 8. The third joint is the broadest. The three first joints form together a broad cone, and the fourth an inverse truncate cone; the latter is distinguished by convergent longitudinal ribs. Pores regular, circular, alternating with the ribs in the fourth joint. Truncate mouth hyaline, half as broad as the third joint.

_Dimensions._--Length of the shell (with four joints) 0.2. Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.05, _d_ 0.08; breadth (in the middle part) 0.1.

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

12. _Lithocampe diaphana_, Haeckel.

_Eucyrtidium diaphanum_, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 309.

Shell smooth, hyaline, spindle-shaped, decreasing uniformly towards both poles, with three distinct strictures. Four joints of different lengths; the second and third equal in breadth, twice as broad and three times as long as the first and the fourth. Pores very small and scarce, in transverse interrupted rows, commonly two rows in the first, two or three in the second, three or four in the third, and only one in the last joint. Mouth constricted, two-thirds as broad as the fourth joint.

_Dimensions._--Length of the shell (with four joints) 0.13. Length of the single joints, _a_ 0.015, _b_ 0.05, _c_ 0.05, _d_ 0.015; breadth (in the middle part) 0.06, mouth 0.02.

_Habitat._--South Atlantic, Station 335, depth 1425 fathoms.

{1506}13. _Lithocampe hispida_, Haeckel.

_Lithocampe hispida_, Haeckel, 1862, Monogr. d. Radiol., p. 318.

_Eucyrtidium hispidum_, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 298; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, p.
291, Taf. ii. fig. 19.

Shell thorny, slenderly ovate, or nearly spindle-shaped, with four sharp strictures. Five joints of different lengths = 3 : 3 : 4 : 6 : 4. The fourth joint is the broadest, and nearly twice as broad as the constricted mouth. Pores small, circular, separated by longitudinal, spiny ribs, regularly disposed in transverse rows; three rows in the first and second, four rows in the third and fifth, six rows in the fourth joint.

_Dimensions._--Length of the shell (with five joints) 0.1. Length of the single joints, _a_ 0.015, _b_ 0.015, _c_ 0.02, _d_ 0.03, _e_ 0.02; greatest breadth 0.05.

_Habitat._--Arctic Ocean (in different depths), Ehrenberg.

14. _Lithocampe tumidula_, Haeckel.

_Lithocampe tumidula_, Haeckel, 1862, Monogr. d. Radiol., p. 318.

_Eucyrtidium tumidulum_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol.
xxii. p. 5, pl. i. fig. 11.

_Eucyrtidium tumidulum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 293, Taf. ii. fig. 12.

? _Eucyrtidium increscens_, Ehrenberg, 1861, Monatsber. d. k. preuss.
Akad. d. Wiss. Berlin, p. 299.

? _Lithocampe increscens_, Haeckel, 1862, Monogr. d. Radiol., p. 318.