Chapter XXXII: Section IV: STICHOCYRTIDA, Haeckel, 1862, Monogr. d. Radiol., p. 280, 312 (7)

_Dictyocha diadema_, Haeckel, 1881, Prodromus.

Each pileated piece of the skeleton is an eight-sided pyramid, like that of the two foregoing species, but differing in the number and distribution of the teeth or spines, which are thirty-two. From the eight corners of the basal ring start eight long, nearly horizontal perradial spines, which bear on each side a smaller, nearly vertically descending spine. From the eight corners of the upper ring ascend also eight perradial spines, alternating with the eight interradial beams, which connect the two rings.

_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.02.

_Habitat._--South Pacific, Station 293, depth 2025 fathoms.

Genus 664. _Cannopilus_,[282] n. gen.

_Definition._--#Cannorrhaphida# with a skeleton composed of pileated pieces, each of which is a small truncated pyramid with two girdles of meshes (the apical ring being fenestrated).

The genus _Cannopilus_ represents the most highly developed form of Dictyochida. Each piece of the skeleton is a little fenestrated hat or topped pyramid, as in _Distephanus_. But the apical mesh is simple in the latter, in the former it is divided into several meshes by bars which start in a centripetal direction from the upper ring. Therefore we find two annular rows of meshes, one above the other; an apical or upper row of smaller meshes and a basal or lower row of larger meshes. In the apex of the little {1568}hat is either a central mesh or an apical spine. Other spines arise from the basal ring, as in the former genera. The number of corner-spines on the basal ring is either four, six, or eight (in individual abnormalities also five or seven).

1. _Cannopilus superstructus_, Haeckel.

_Dictyocha superstructa_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 80; Mikrogeol., Taf. xxii. fig. 45.

Each pileated piece of the skeleton is a reticulated four-sided pyramid. The base of it (or the lower ring) is a square, from the four perradial corners of which start four centrifugal horizontal spines. In the centres of the four basal bars (or the sides of the square) arise four interradial beams, which unite in the second (or upper) square ring. This latter forms a second (but much smaller) four-sided pyramid, the apex of which is truncated. Therefore the little hat bears nine meshes; around the large central opening four upper smaller and four lower larger quadrangular meshes.

_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.01.

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

2. _Cannopilus diplostaurus_, n. sp. (Pl. 114, fig. 10).

Each pileated piece of the skeleton is a truncated quadrangular pyramid. From the corners of the square basal ring start four perradial, nearly horizontal, spines. Between these arise four interradial beams, which are united above by an upper square ring. This latter is divided into four small square meshes by a regular cross of perradial bars, the distal ends of which are prolonged into four short ascending spines. In the centre of the cross arises a vertical apical spine.

_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.016.

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

3. _Cannopilus calyptra_, Haeckel.

_Dictyocha heptacanthus_, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 208; Mikrogeol., 1854, Taf. xix. fig. 39 (?).

Each pileated piece of the skeleton is a truncated six-sided pyramid, like that of _Dictyocha speculum_, but distinguished by the reticulation of the upper (smaller) ring, which is divided by six beams into six meshes, lying in the horizontal plane of the upper ring. Six peripheral spines on the corners of the lower ring. (The irregular form, figured by Ehrenberg as _Dictyocha heptacanthus_, _loc. cit._, is probably only an individual abnormality with seven peripheral spines, instead of six; similar abnormalities occur also among the regular hexagonal forms which I found in the Tertiary rocks of Caltanisetta (Sicily).

_Dimensions._--Diameter of the basal ring 0.05, of the apical ring 0.02.

_Habitat._--Fossil in Tertiary deposits of Greece and Sicily.

{1569}4. _Cannopilus hemisphæricus_ (Haeckel).

_Dictyocha hemisphærica_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad.
d. Wiss. Berlin, p. 266.

Each pileated piece of the skeleton is nearly hemispherical, with thirteen meshes; six lower and larger meshes in the sides of the truncated six-sided pyramid, seven others in the convex surface of the upper ring (one central with six surrounding it). From the six corners of the lower ring arise six horizontal perradial spines. From the inside of the same ring (probably on the side of the six ascending interradial beams) spring six centripetal teeth.

_Dimensions._--Diameter of the basal ring 0.02, of the apical ring 0.01.

_Habitat._--North Atlantic; Bermuda (Bailey).

5. _Cannopilus cyrtoides_, n. sp. (Pl. 114, figs. 11, 12).

_Dictyocha cyrtoides_, Haeckel, 1881, Prodromus.

Each pileated piece of the skeleton is an eight-sided truncated pyramid, or nearly hemispherical. From the basal ring arise twenty-four thorns or teeth, eight longer perradial centrifugal teeth placed almost horizontally, and between these sixteen shorter adradial teeth, directed downwards and somewhat centripetally. The network of the small hat is composed of seventeen meshes, arranged in two rows. The eight lower meshes are hexagonal, separated by six interradial ascending beams, and twice as large as the eight upper pentagonal meshes, which are separated by eight perradial beams, and enclose an apical central mesh.

_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.005.

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

Family LXXIII. #AULACANTHIDA#, Haeckel (Pls. 102-105).

_Aulacanthida_, Haeckel, 1862, Monogr. d. Radiol., p. 262.

_Definition._--PHÆODARIA with an incomplete skeleton, composed of numerous hollow radial tubes, which pierce the spherical calymma and touch with their proximal ends the surface of the tripylean central capsule.

The family #Aulacanthida# represents a large and interesting group of PHÆODARIA, differing from all other families of this legion in the possession of numerous large radial tubes, which pierce the gelatinous and alveolated calymma in a radial direction, and come in contact with the outer surface of the central capsule by their inner or proximal ends, whilst their outer or distal ends project over the surface of the spherical calymma, and develop a great variety of manifold branches and terminal appendages. Usually (with the exception of a single genus only) the surface of the calymma is covered by an {1570}arachnoidal veil or mantle, composed of thousands of very fine, hollow, tangential needles. The skeleton therefore is incomplete, without any direct connection between the isolated pieces, just as in the preceding Cannorrhaphida, but the latter never possess the large, hollow, cylindrical, radial tubes, which are characteristic of all Aulacanthida.

The spherical body of the Aulacanthida has usually a diameter of 1 to 2 mm., and including the radial tubes, of 4 to 5 mm. or more. Some species are very common and cosmopolitan, and some genera contain numerous species, distributed widely over all oceans. In spite of their considerable size and wide distribution, only one species of this great family has been hitherto known, having been discovered by me at Messina in 1859, and described in my Monograph as _Aulacantha scolymantha_ (1862, p. 263, Taf. ii. figs. 1, 2, and Taf. iv. figs. 1-5). I there founded for it the peculiar subfamily Aulacanthida, and annexed it to the Thalassicollida. The same cosmopolitan species has been subsequently observed at Messina by R. Hertwig, who first recognised the three openings in its central capsule, and therefore united it with his TRIPYLEA (Organism. d. Radiol., 1879, p. 88, Taf. ix. figs. 3, 4; Taf. x. figs. 7, 10). The rich collection of the Challenger has added an astonishing number of new and interesting forms of Aulacanthida, so that I can describe here not less than six genera and fifty-eight species. The majority are inhabitants of the colder parts of the South Pacific and South Atlantic, at great depths, whilst a few species only are found in the tropics.

The structure of the body in all Aulacanthida seems to be similar in all important points, and the differences by which we are enabled to separate this great number of species are mainly produced by differences in the development of the radial tubes, their form and their polymorphous apophyses. The entire body represents a rather firm jelly-sphere of 1 to 2 mm. diameter (rarely less or more); the peripheral layer of the spherical calymma is rather clear and transparent, whilst its central part is dark and opaque, containing the big phæodium and the enclosed central capsule. The diameter of the latter is usually between 0.1 and 0.3, often 0.4 to 0.5, or even more. The gelatinous calymma, in the centre of which the capsule is placed, always contains numerous, large, spherical or roundish alveoles, similar to those of _Thalassicolla_, and between them a delicate network of sarcode (Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. 1).

The spherical surface of the calymma is nearly always protected by that characteristic arachnoidal veil or mantle, which is composed of thousands of very fine tangential needles, densely interwoven in all tangential directions but never directly connected. They are wanting in a single genus only, in _Aulactinium_ (Pl. 101, figs. 6-8). This genus, therefore, may represent a separate subfamily, the Aulactinida, whilst all other genera protected by that mantle constitute the subfamily Aulographida. The tangential needles always seem to have the same shape as I have accurately described, in 1862, of _Aulacantha scolymantha_. They are constantly smooth, very thin and fragile, but also very elastic cylinders of silica, of equal breadth throughout their whole length, and seem {1571}to be open at both ends, since they are easily and constantly filled by air when dried. Their length is usually between 0.2 and 0.3 mm., rarely less than 0.15 or more than 0.5; their diameter is always less than 0.001, usually less than 0.0005.

The large radial tubes of the Aulacanthida constitute the most characteristic structures of this family, and are always so placed that their inner or proximal ends are in loose contact with the outer surface of their central capsule (upon which they rest), whilst their outer or distal ends are more or less prominent over the spherical surface of the calymma. Their position, therefore, is rather loose and movable, since they are fixed only by the consistence of the jelly of the surrounding calymma, and on the surface of the latter by the covering veil or the mantle of tangential needles (compare Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. 1). Their number seems never to be fixed, and is probably very variable in different species. I found, in 1859, in the common _Aulacantha scolymantha_, the number varying from thirty to one hundred and fifty (_loc. cit._, p. 264). So also in _Aulographis pandora_, _Aulospathis variabilis_, and some other common species, numerous specimens of which I could compare, I found their number very variable, being in one and the same species sometimes only from ten to twenty, at other times from fifty to eighty, and sometimes even from one hundred to one hundred and fifty or more. Perhaps the number increases with the age and the increasing size of the calymma.

The radial tubes are always cylindrical (circular in transverse section), never angular or prismatic. Usually they are straight, more rarely slightly curved (Pl. 105, figs. 1, 2; Pl. 101, fig. 6). The cylinders are usually more or less tapering towards both ends, sometimes even spindle-shaped; the inner or proximal end is always simple and rounded, often slightly swollen or inflated, and ovate; the outer or distal end is often thickened, club-shaped, and exhibits the greatest variety in form and ramification. The length of the radial tubes is usually from 1 to 3 mm., rarely less than 0.8, or more than 3.2; their diameter is usually between 0.02 and 0.03, rarely less than 0.01 or more than 0.05. The smallest radial tubes are found in _Aulactinium_, the largest in _Aulospathis_.

The siliceous wall of the cylindrical radial tubes is usually very thin, fragile, and perfectly structureless. Only in a few species, mainly of _Aulographis_, does the wall become very thick and composed of concentric cylindrical layers (Pl. 105, figs. 6-11). Their cavity is wide and simple, and filled up by jelly (not by sarcode, as I supposed in my first description). The simple cavity of the tubes, though not smaller than in the radial tubes of the Aulosphærida, Circoporida and Tuscarorida, never contains the characteristic axial filament with its branches, which is constantly found in the latter families. According to the description of R. Hertwig, the tubes are perfectly closed and have no opening. I suppose, however, that a small opening always exists in the centre of the rounded base, and perhaps a second on the distal apex. Otherwise the circumstance that the entire and well-preserved tubes become easily and constantly filled {1572}up by air, when purified by hot mineral acids and afterwards dried, cannot be explained. I suppose that the jelly contained in the cavity of the tubes remains in constant connection by these openings with the jelly of the surrounding calymma.

The distal ends of the radial tubes exhibit in the Aulacanthida the greatest variety in the production of different branches and capturing apparatus, and this serves for the distinction of the genera and subgenera here described. In two genera only (in _Aulactinium_ Pl. 101, figs. 6-8; and in _Aulacantha_, Pl. 105, fig. 16), the distal ends are simple, not branched. In the four other genera they are armed with terminal branches, which are usually arranged in elegant verticils. The greatest variety in the formation of these verticils is developed in _Aulographis_ (Pl. 103). The single branches of the terminal verticils are here simple, whilst in the closely allied _Auloceros_ they are forked or elegantly ramified (Pl. 102). _Aulospathis_, the biggest of all Aulacanthida, is distinguished by the possession of a verticil of lateral branches, placed beyond the terminal verticil, immediately above the veil of tangential needles (Pl. 104). _Aulodendron_, finally, possesses lateral and terminal branches, which are irregularly scattered.

The branches of the radial tubes are rarely straight, usually more or less curved, either simple or again ramified. Their surface is either smooth or armed with small spines or recurved teeth, often elegantly dentated or serrated (Pl. 103, figs. 20-27; Pl. 105, figs. 7-13). Their distal ends are either simply pointed or armed with a spathilla, or a small crown of verticillate, usually recurved teeth (Pl. 104, figs. 4-17). The variety and elegance of these minute armatures are very interesting, the more so as they occur in very similar and analogous forms among the Aulosphærida, the Coelographida, and other PHÆODARIA.

The _central capsule_ of the Aulosphærida and its large nucleus ("Binnenbläschen"), as well as the surrounding alveolate calymma ("Alveolen-Hülle"), and the enclosed dark phæodium ("dunkels Pigment") were first described in my Monograph (1862, _loc. cit._, p. 362). Their minute structure has been examined afterwards very accurately by R. Hertwig (1879, _loc. cit._, p. 95). The numerous well-preserved preparations of the Challenger (stained with carmine and preserved in glycerine) which I could examine, confirmed in all respects the detailed description of Hertwig (compare Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. 1).

The spherical or subspherical central capsule is usually slightly depressed in the shortened main axis. Its diameter is usually between 0.1 and 0.3, rarely less than 0.08 or more than 0.4 mm. Its outer membrane (_e_) is thick and double-contoured, separated by a clear interval from the very thin but firm inner membrane (_i_). The large astropyle, or the main-opening on the oral pole of the main axis, is closed by a large, convex, radiate operculum (_o_), from which arises a short tubular proboscis. On both sides of the opposite aboral pole (to the right and left) are two conical parapylæ or secondary openings (_u, u_). The space between the inner membrane of the capsule and {1573}the nucleus is filled up by protoplasm, containing numerous spherical vacuoles of equal size (_v_); each vacuole encloses a small, dark, fat-granule. The large nucleus (_n_) is either spherical or lenticular, and more or less depressed in the main axis; its diameter is usually about half as great as that of the enclosing capsule, 0.05 to 0.15, rarely less or more; it contains, enclosed in a clear mass, numerous dark, roundish or oblongish nucleoli (_l_).

Numerous preparations of Aulacanthida exhibited a central capsule with two nuclei (Pl. 101, fig. 6), or a calymma with two central capsules (Pl. 104, figs. 1, 3); so that the process of propagation by self-division, observed already in many different PHÆODARIA, seems to happen very frequently in the Aulacanthida. The voluminous phæodium is usually about twice or three times as large as the central capsule, and covers its oral or anterior half; the colour of the roundish phæodella composing it is sometimes more green or brown, at other times more blackish. The roundish alveoles, which fill up the rather firm jelly of the calymma, exhibit nearly the same shape as in the common _Thalassicolla nucleata_. The surface of the calymma is usually protected by the dense veil of tangential needles, and often forms conical or tent-shaped elevations around the bases of the piercing radial tubes (Pl. 102, fig. 1).

_Synopsis of the Genera of Aulacanthida._

{ Surface of the calymma
{ naked, without tangential
{ needles, 665. _Aulactinium_.
Radial tubes simple, {
without lateral and { Surface of the calymma
terminal branches. { covered by a veil of
{ tangential needles, 666. _Aulacantha_.

Radial tubes without { Terminal branches simple, 667. _Aulographis_.
lateral branches, but {
with a verticil of { Terminal branches forked
terminal branches. { or again ramified, 668. _Auloceros_.

{ Lateral branches
Radial tubes with { verticillate, 669. _Aulospathis_.
lateral and with {
terminal branches. { Lateral branches
{ irregularly scattered,
{ not verticillate, 670. _Aulodendron_.

Subfamily 1. AULACTINIDA, Haeckel.

_Definition._--#Aulacanthida# without external veil of tangential needles on the surface of the calymma.

Genus 665. _Aulactinium_,[283] n. gen.

_Definition._--#Aulacanthida# without a veil of tangential needles, with simple radial tubes, which bear neither lateral nor terminal branches.

{1574}The genus _Aulactinium_ differs from all the other Aulacanthida in the complete absence of the characteristic fine tangential needles, which constitute in the latter an arachnoidal veil or mantle around the spherical calymma. We accordingly divide the whole family into two subfamilies, the Aulactinida with a naked calymma, and the Aulographida with a veil of tangential needles. The radial tubes possess in the few species of _Aulactinium_ observed a very simple shape, as in the closely allied _Aulacantha_.

1. _Aulactinium actinastrum_, n. sp. (Pl. 101, figs. 6, 7).

Radial tubes slenderly spindle-shaped, slightly curved, gradually tapering from the middle towards both ends. The proximal two-thirds of the tubes enclosed in the calymma are smooth; the distal freely prominent third is armed with six to eight equidistant verticils of small conical teeth (ten to fifteen in each verticil).

_Dimensions._--Length of the tubes 0.5 to 1.5, breadth 0.02.

_Habitat._--South Pacific, Station 289, depth 2550 fathoms.

2. _Aulactinium actinelium_, n. sp. (Pl. 101, fig. 8).

Radial tubes cylindrical, straight, slightly tapering towards both ends. Proximal two-thirds smooth, the distal third studded with numerous small recurved thorns.

_Dimensions._--Length of the tubes 0.6 to 0.9, breadth 0.02.

_Habitat._--South Pacific, Station 293, depth 2025 fathoms.

3. _Aulactinium actinosphærium_, n. sp.

Radial tubes cylindrical, straight, smooth, of nearly equal breadth throughout their whole length, without thorns and spathillæ, pointed at both ends.

_Dimensions._--Length of the tubes 1.6 to 2.2, breadth 0.02 to 0.03.

_Habitat._--Antarctic Sea, Station 157, depth 1950 fathoms.

Subfamily 2. AULOGRAPHIDA, Haeckel.

_Definition._--#Aulacanthida# with an external veil of interwoven, very numerous and thin, hollow, tangential needles, entirely covering the surface of the calymma.

Genus 666. _Aulacantha_,[284] Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 799.

_Definition._--#Aulacanthida# with a veil of tangential needles, and with simple radial tubes, which bear neither lateral nor terminal branches.

{1575}The genus _Aulacantha_, hitherto the only representative of this family, was founded by me in 1860 for the cosmopolitan _Aulacantha scolymantha_, the most common and most widely distributed of all the members of the family. It is the simplest form of the Aulographida, or of those Aulacanthida in which the spherical surface of the calymma is densely covered with interwoven tangential needles. The large radial tubes of _Aulacantha_ possess a very simple shape, as in the preceding _Aulactinium_, and have neither lateral nor terminal branches.

1. _Aulacantha scolymantha_, Haeckel.

_Aulacantha scolymantha_, Haeckel, 1862, Monogr. d. Radiol., p. 263, Taf.
ii. figs. 1, 2, Taf. iv. figs. 1-5.

_Aulacantha scolymantha_, R. Hertwig, 1879, Organism. d. Radiol., p. 88,
Taf. ix. fig. 3, Taf. x. figs. 7-10.

Radial tubes cylindrical, straight, of nearly equal breadth throughout their whole length, somewhat inflated on the proximal basal end, smooth throughout the greater part of their length, but in the distal third dentate, with numerous (ten to forty) small pointed teeth, which are curved outwards, and shorter than the thickness of the tube.

_Dimensions._--Length of the tubes 0.5 to 2.0, breadth 0.01 to 0.02.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; at many Stations; surface and at various depths; the most common of all Aulacanthida.

2. _Aulacantha tubulosa_, n. sp.

Radial tubes cylindrical or nearly spindle-shaped, straight, gradually tapering towards the two pointed ends, twice as broad in the middle third as in the outer and inner third, smooth in the inner half, dentate in the outer half, with very numerous (one hundred to two hundred) short conical teeth, which are scarcely one-fourth as large as the greatest breadth of the tube.

_Dimensions._--Length of the tubes 0.4 to 0.5, breadth in the middle part 0.02 to 0.03.

_Habitat._--Central Pacific, Stations 271 to 274, surface.

3. _Aulacantha spinosa_, n. sp. (Pl. 105, fig. 4).

Radial tubes cylindrical, straight, of equal breadth throughout their whole length, rounded on the proximal base, smooth in the inner proximal half, dentate or spinescent in the outer distal half, with numerous (fifty to eighty) slender conical teeth, which are curved forwards, increasing in size towards the distal end, and somewhat longer than the breadth of the tube.

_Dimensions._--Length of the tubes 0.8 to 1.2, breadth 0.015 to 0.02.

_Habitat._--North Pacific, Stations 241 to 253, surface.

{1576}4. _Aulacantha cannulata_, n. sp. (Pl. 105, fig. 16).

Radial tubes cylindrical in the inner proximal half, prismatic in the outer distal half, with from three to six, usually four, prominent, thick, parallel edges, which are dentate towards the thicker distal end; their teeth short, conical, directed outwards, scarcely one-fourth as long as the thickness of the tube. The edges are separated in the distal third by more or less deep furrows, like a channelled column.

_Dimensions._--Length of the tubes 1.2 to 2.5, breadth 0.03 to 0.04.

_Habitat._--South Pacific, Stations 291 to 293, surface.

5. _Aulacantha clavata_, n. sp.

Radial tubes more or less irregularly curved, in the inner proximal half slenderly conical, and gradually tapering towards the inflated base, in the outer distal half club-shaped, armed with a few (five to twenty) short conical teeth.

_Dimensions._--Length of the tubes 1.0 to 1.2, breadth in the middle pact 0.01, in the distal part 0.04.

_Habitat._--South Atlantic, Station 318, depth 2040 fathoms.

6. _Aulacantha lævissima_, n. sp.

Radial tubes cylindrical, straight, of nearly equal breadth throughout their whole length; the inner proximal end rounded, the outer distal end pointed. Surface of the tubes perfectly smooth, without any teeth. The thickness and length of the simple spicula, as well as the thickness of their wall, are very variable in this species.

_Dimensions._--Length of the tubes 0.5 to 4.2, breadth 0.003 to 0.02.

_Habitat._--North Atlantic, Station 253, Færöe Channel, surface, John Murray.

Genus 667. _Aulographis_,[285] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.

_Definition._--#Aulacanthida# with a veil of tangential needles, and with radial tubes, which bear no lateral branches, but at the distal end a verticil of simple terminal branches.

The genus _Aulographis_, the richest in the number of species among all Aulacanthida, differs from the preceding _Aulacantha_, its ancestral form, in the development of simple terminal branches, which form either a fork or a verticil. The branches are either smooth or spiny, but not ramified as in the following genus, _Auloceros_. Their distal {1577}ends are either simply pointed or bear a terminal spathilla, or a little crown of recurved teeth. According to these differences we may dispose the twenty-six species described into four subgenera.

Subgenus 1. _Aulographantha_, Haeckel.

_Definition._--Terminal branches of the radial tubes simple, smooth, without lateral teeth and terminal spathillæ. Tubes usually thin and fragile.

1. _Aulographis pandora_, n. sp. (Pl. 103, figs. 2-9).

Radial tubes cylindrical, slender, straight or slightly curved, of equal breadth. Terminal branches of the tubes very variable in size and number (two to six, usually three or four), without lateral teeth and terminal spathillæ, slender, conical, slightly curved, directed outwards, twice to four times (rarely five to eight times) as long as the breadth of the tubes. This species is extraordinarily variable in the number and size of the simple terminal branches; the eight tubes, shown in figs. 2 to 9, are all found in one and the same specimen.

_Dimensions._--Length of the tubes 0.5 to 1.5, breadth 0.01 to 0.03; branches 0.02 to 0.12.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; surface and in various depths.

2. _Aulographis bovicornis_, n. sp. (Pl. 103, figs. 12-14).

Radial tubes cylindrical, slender, straight, of equal breadth. Terminal branches usually two (rarely three), smooth, without lateral teeth and terminal spathillæ, eight to ten times as long as the breadth of the tube, pointed, S-shaped, or curved like the horns of an ox.

_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.015 to 0.02; branches 0.1 to 0.2.

_Habitat._--South Atlantic (east of Buenos Ayres), Stations 323 to 325, surface.

3. _Aulographis taumorpha_, n. sp. (Pl. 103, fig. 16).

Radial tubes cylindrical, slender, straight, gradually tapering towards the pointed proximal end. Terminal branches constantly two, opposite in a tangential, slightly concave or nearly straight line, ten to twelve times as long as the breadth of the tube, smooth, straight in the proximal part, recurved in the distal part.

_Dimensions._--Length of the tubes 0.7 to 0.8, breadth 0.01 to 0.015; branches 0.1 to 0.15.

_Habitat._--North Pacific, Station 231, depth 2250 fathoms.

{1578}4. _Aulographis triglochin_, n. sp. (Pl. 103, fig. 17).

Radial tubes robust, club-shaped at the distal end. Terminal branches three (rarely two or four), widely divergent, geniculated and recurved, smooth, without lateral teeth and terminal spathillæ.

_Dimensions._--Length of the tubes 1.2 to 1.8, breadth 0.02; branches 0.12 to 0.15.

_Habitat._--Central Pacific, Stations 271 to 274, surface.

5. _Aulographis cruciata_, n. sp. (Pl. 103, fig. 25).

Radial tubes slender, cylindrical, of equal breadth. Terminal branches almost constantly four, equal, regularly crossed (very rarely three or five), slender, straight or slightly curved, smooth, divergent outwards, six to eight times as long as the breadth of the tube.

_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.02; branches 0.12 to 0.15.

_Habitat._--South Atlantic, Stations 325 to 332, surface.

6. _Aulographis ancorata_, n. sp. (Pl. 103, fig. 21).

Radial tubes slender, cylindrical, straight. Terminal branches constantly four, equal, regularly crossed, arcuato-recurved or nearly semicircular, smooth, six to eight times as long as the breadth of the tube. Resembling an anchor with four teeth.

_Dimensions._--Length of the tubes 0.5 to 0.7, breadth 0.012 to 0.015; branches 0.07 to 0.09.

_Habitat._--South-west Atlantic, Station 318, depth 2040 fathoms.

7. _Aulographis stellata_, n. sp. (Pl. 103, figs. 23, _a_-_c_).

Radial tubes club-shaped, gradually thickened towards the distal end. Terminal branches stellate, numerous (five to ten or more), diverging in all directions, smooth, straight or slightly curved, slenderly conical, three to five times as long as the distal breadth of the tube. The branches are very variable in size, sometimes very small (figs. _a_, _b_).

_Dimensions._--Length of the tubes 0.4 to 0.8, breadth 0.02; branches 0.01 to 0.02.

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

8. _Aulographis penicillata_, n. sp.

Radial tubes slender, cylindrical, of equal breadth. Terminal branches pencil-shaped, smooth, very numerous (twenty to thirty or more), diverging outwards, curved, eight to ten times as long as the breadth of the tube, very thin and fragile, resembling a brush.

_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.02; branches 0.15 to 0.2.

_Habitat._--North Atlantic (Antilles), Weber, surface.

{1579}9. _Aulographis pistillum_, n. sp. (Pl. 105, fig. 6).

Radial tubes club-shaped, robust, straight, gradually thickened towards the distal end. Terminal branches eight to ten (usually nine), conical, smooth, slightly curved, divergent outwards like a regular corona.

_Dimensions._--Length of the tubes 0.5 to 0.6, distal breadth 0.04; branches 0.08.

_Habitat._--North Atlantic, Station 354, depth 1675 fathoms.

Subgenus 2. _Aulographella_, Haeckel.

_Definition._--Terminal branches of the radial tubes without terminal spathillæ, but with lateral teeth or secondary spines. (Tubes usually very stout and robust, club-shaped.)

10. _Aulographis triæna_, n. sp. (Pl. 105, fig. 8).

Radial tubes club-shaped, straight, tapering gradually towards the rounded proximal end. Terminal branches constantly three, divergent, very stout, eight to ten times as long as the breadth of the tube, each studded with three to six irregular, conical, secondary spines. Sometimes the branches become forked, the species passing over into _Auloceros cervinus_.

_Dimensions._--Length of the tubes 1.2 to 1.5, breadth 0.004 to 0.06; branches 0.3 to 0.5.

_Habitat._--South Pacific, Station 299, depth 2160 fathoms.

11. _Aulographis martagon_, n. sp. (Pl. 105, fig. 7).

Radial tubes club-shaped or slenderly conical, strongly thickened towards the distal end. Terminal branches six to nine, conical, slightly curved, divergent outwards, studded outside with small, conical, secondary spines, twice to three times as long as the breadth of the tube.

_Dimensions._--Length of the tubes 1.0 to 1.2, breadth 0.04 to 0.05; branches 0.1 to 0.15.

_Habitat._--South Atlantic, Station 318, depth 2040 fathoms.

12. _Aulographis flammabunda_, n. sp. (Pl. 105, fig. 9).

Radial tubes club-shaped, more or less curved, with thickened distal ends. Terminal branches three to six, conical, very stout, three to four times as long as the breadth of the tube, densely studded with numerous, crowded, conical, secondary spines, which are very irregular and more or less curved, resembling the flames of a fire.

_Dimensions._--Length of the tubes 1.0 to 1.2, distal breadth 0.08 to 0.1; branches 0.2 to 0.4.

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

{1580}13. _Aulographis gemmascens_, n. sp. (Pl. 105, fig. 11).

Radial tubes club-shaped, more or less curved, with thickened distal end. Terminal branches three to nine (usually three larger and six smaller) stout, conical, studded with irregular, straight, conical, secondary spines, crowded and densely aggregated, like the leaves in a bud.

_Dimensions._--Length of the spines 1.5 to 1.8, distal breadth 0.07 to 0.1; branches 0.2 to 0.6.

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

14. _Aulographis flosculus_, n. sp. (Pl. 105, fig. 10).

Radial tubes club-shaped, straight, tapering gradually towards the rounded proximal end. Terminal branches nine to twelve, stout, conical, twice to three times as long as the breadth of the tube, studded with irregular secondary spines, connected in the proximal half by a solid, cap-shaped, flinty lamella, so that the terminal corona resembles a flower. The hollow canal of the tube sends a thin branch into each branch of the crown.

_Dimensions._--Length of the tubes 1.2 to 1.8, distal breadth 0.04 to 0.05; branches 0.1 to 0.2.

_Habitat._--North Atlantic, Færöe Channel (Gulf Stream), John Murray, depth 600 fathoms.

Subgenus 3. _Aulographidium_, Haeckel.

_Definition._--Terminal branches of the radial tubes armed with terminal spathillæ (or whorls of small radial teeth), but without lateral denticles or spines.

15. _Aulographis furcula_, n. sp. (Pl. 103, figs. 10, 11).

Radial tubes cylindrical, slender, slightly curved. Terminal branches usually two, sometimes on single tubes three, eight to ten times as long as the tube is broad, strongly curved, ascending vertically from a horizontal base, with a terminal spathilla of four crossed teeth at the distal end.

_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.006 to 0.008; branches 0.06 to 0.08.

_Habitat._--North-west Pacific (off Japan), Station 231, depth 2250 fathoms.

16. _Aulographis triangulum_, n. sp. (Pl. 103, fig. 15).

Radial tubes cylindrical, slender, straight. Terminal branches constantly three, slender, slightly curved, nearly horizontally (tangentially) expanded, eight to ten times as long as the tube is broad, with a terminal spathilla of four recurved teeth which are opposite in pairs. Since the angles between the three branches are equal (= 120°) they correspond to the axes of an equilateral triangle.

_Dimensions._--Length of the tubes 1.2, breadth 0.015 to 0.02; branches 0.1 to 0.12.

_Habitat._--South Pacific, Station 289, depth 2550 fathoms.

{1581}17. _Aulographis tetrancistra_, n. sp. (Pl. 103, fig. 22).

Radial tubes slender, cylindrical, straight. Terminal branches four to six (usually four), eight to ten times as long as the tube is broad, slightly curved and widely divergent, with a terminal spathilla of four crossed recurved teeth.

_Dimensions._--Length of the tubes 0.5 to 0.7, breadth 0.01; branches 0.08 to 0.1.

_Habitat._--South Pacific, Station 285, depth 2375 fathoms.

18. _Aulographis hexancistra_, n. sp. (Pl. 103, figs. 18, 19).

Radial tubes club-shaped, slightly curved, gradually thickened from the proximal to the distal end. Terminal branches four to eight (usually six in the majority of tubes), widely divergent, nearly straight, three to four times as long as the tube is broad, with a terminal spathilla of six (rarely five) recurved teeth.

_Dimensions._--Length of the tubes 0.4 to 0.6, breadth 0.01 to 0.02; branches 0.04 to 0.08.

_Habitat._--North Pacific, Stations 244 to 253, depth 2050 to 3125 fathoms.

19. _Aulographis polyancistra_, n. sp.

Radial tubes club-shaped, straight, thickened towards the distal end. Terminal branches ten to twenty, smooth, strongly curved, disposed in a corona, six to eight times as long as the tube is broad, each with a terminal spathilla of eight to twelve radial teeth.

_Dimensions._--Length of the tubes 0.6 to 0.8, distal breadth 0.02; branches 0.12 to 0.16.

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

20. _Aulographis asteriscus_, n. sp. (Pl. 103, fig. 24).

Radial tubes slender, cylindrical, straight, equally broad. Terminal branches six to nine, widely divergent, disposed in a radiate corona, around a central branch, which is the distal prolongation of the tube itself. Each branch bears a stellate terminal spathilla, composed of ten to twenty conical teeth, which radiate in all directions.

_Dimensions._--Length of the tubes 0.5 to 0.8, breadth 0.02; branches 0.06 to 0.09.

_Habitat._--South Atlantic, Station 318, depth 2040 fathoms.

Subgenus 4. _Aulographonium_, Haeckel.

_Definition._--Terminal branches of the radial tubes armed with numerous lateral denticles, and with terminal spathillæ (or whorls of small radial teeth).

{1582}21. _Aulographis dentata_, n. sp. (Pl. 103, fig. 20).

Radial tubes slender, cylindrical, equally broad, scarcely inflated at the distal end. Terminal branches six to eight, curved, disposed in a corona around a straight central branch, eight to ten times as long as the tube is broad, armed with numerous stout recurved lateral denticles and with a terminal spathilla of five or six recurved teeth.

_Dimensions._--Length of the tubes 1.5 to 2.5, breadth 0.03; branches 0.15 to 0.2 long.

_Habitat._--North Atlantic, Station 354, depth 1675 fathoms.

22. _Aulographis pulvinata_, n. sp. (Pl. 103, fig. 26).

Radial tubes club-shaped, straight, gradually thickened towards the distal end, which bears a broad, circular, biconvex cushion. The margin of this cushion bears two alternating verticils of radially divergent, straight, terminal branches, which are twice to three times as long as the tube is broad. Each branch is armed with two opposite lateral rows of numerous small denticles, and bears a terminal spathilla with six to eight recurved radial teeth.

_Dimensions._--Length of the tubes 2.0 to 2.4, distal breadth 0.03 to 0.07; branches 0.05 to 0.08 long.

_Habitat._--South-east Pacific (off Valparaiso), Station 298, depth 2225 fathoms.

23. _Aulographis tripentas_, n. sp. (Pl. 105, fig. 13, 13_a_).

Radial tubes club-shaped, straight, thickened towards the inflated distal end, which bears three alternating verticils of terminal branches, each with five radial branches. The ten branches of the inner and outer verticils are perradial, smooth; the alternating five branches of the middle verticil are armed with recurved lateral denticles. Each of the fifteen branches bears a terminal spathilla with five to seven recurved teeth.

_Dimensions._--Length of the spines 2.0 to 2.5, distal breadth 0.03 to 0.06; branches 0.1 long.

_Habitat._--South-east Pacific (off Juan Fernandez), Station 299, depth 2160 fathoms.

24. _Aulographis verticillata_, n. sp. (Pl. 105, fig. 12, 12_a_).

Radial tubes cylindrical, equally broad, with an inflated ellipsoidal knob at the distal end. This knob bears twenty to thirty slender, slightly curved, terminal branches, which are regularly arranged in five radial or meridional rows, and in four to six concentric verticils. The branches are five to ten times as long as the tube is broad, and armed with two opposite rows of lateral denticles, and with a terminal spathilla of six to eight recurved teeth.

_Dimensions._--Length of the tubes 1.5 to 1.8, breadth 0.01 to 0.02; branches 0.5 to 1.0 long.

_Habitat._--South Pacific, Station 293, depth 2025 fathoms.

25. _Aulographis serrulata_, n. sp. (Pl. 103, fig. 27).

Radial tubes club-shaped, curved, thickened towards the inflated ellipsoidal distal end, which bears a bunch of fifteen to twenty-five terminal branches, arranged more or less regularly in radial {1583}or meridional rows and concentric horizontal verticils. The branches are irregularly curved, twice to four times as long as the distal end of the tube, armed with two opposite rows of lateral denticles, and at the distal end with a spathilla of six radial teeth.

_Dimensions._--Length of the tubes 1.5 to 1.8, breadth 0.02 to 0.04; branches 0.1 to 0.15 long.

_Habitat._--North Pacific, Stations 253 and 254, depth 3025 to 3125 fathoms.

26. _Aulographis candelabrum_, n. sp. (Pl. 103, fig. 1).

Radial tubes club-shaped, straight, thickened towards the distal end and constricted beyond the ovate, inflated, terminal knob. This knob is similar to a candelabrum and bears a corona of six to nine strongly curved terminal branches, which are eight to ten times as long as the tube is broad, armed with scattered lateral denticles, and with a spathilla of five to seven radial teeth.

_Dimensions._--Length of the tubes 1.6 to 2.4, breadth 0.03 to 0.05; branches 0.2 to 0.3 long.

_Habitat._--South-east Pacific (off Juan Fernandez), Station 300, depth 1375 fathoms.

Genus 668. _Auloceros_,[286] n. gen.

_Definition._--#Aulacanthida# with a veil of tangential needles, and with radial tubes, which bear no lateral branches, but at the distal end a verticil of ramified or forked terminal branches.

The genus _Auloceros_ differs from the preceding closely allied _Aulographis_, its ancestral form, in the ramification of the verticillate terminal branches. They are either simply forked or again ramified, and their distal ends are either simply pointed or armed with a terminal spathilla, or a little crown of recurved teeth. Some forms of this genus belong to the most elegant and graceful PHÆODARIA, as the _Auloceros elegans_ figured, which I observed living in the Indian Ocean.

Subgenus 1. _Auloceræa_, Haeckel.

_Definition._--Distal ends of the terminal branches pointed, smooth, without spathilla (or corona of radiate denticles).

1. _Auloceros furcosus_, n. sp. (Pl. 102, figs. 2-6).

Radial tubes slender, spindle-shaped or nearly cylindrical, more or less tapering towards the two ends. Terminal branches slender, curved, twice to four times as long as the tube is broad, very variable in number (usually two or three, rarely four, five, or six; compare figs. 2-6), once or twice forked; the secondary branches are short, irregular, and pointed. No terminal spathillæ. {1584}In some specimens of this species all the tubes bear two or three terminal branches, whilst in others there are tubes with four, five, or six branches intermingled. When the number of the terminal branches is constant in single localities, this transformistic or "Darwinian" species may be divided into the following "subspecies:" (1) _Auloceros pandora_ (with variable numbers); (2) _Auloceros bifurca_ (fig. 2); (3) _Auloceros trifurca_ (fig. 3); (4) _Auloceros quadrifurca_ (fig. 4); (5) _Auloceros quinquefurca_ (fig. 5); (6) _Auloceros sexfurca_ (fig. 6).

_Dimensions._--Length of the tubes 1.5 to 2.5, breadth 0.02 to 0.03; branches 0.05 to 0.15 long.

_Habitat._--North Pacific, Stations 231 to 253, surface and at various depths.

2. _Auloceros trigeminus_, n. sp. (Pl. 102, fig. 7).

Radial tubes club-shaped, gradually thickened towards the inflated distal end. Terminal branches short, scarcely longer than the tube is broad, two constantly opposite, each with three equal, conical, short secondary branches. No terminal spathillæ.

_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.02 to 0.03; branches 0.04 to 0.08.

_Habitat._--North Atlantic, Station 353, depth 2965 fathoms.

3. _Auloceros capreolus_, n. sp. (Pl. 102, fig. 8).

Radial tubes cylindrical, equally broad. Terminal branches in two opposite clustered bunches, each with sixteen to eighteen unequal secondary branches. The total length and breadth of each cluster is about four times as great as the tube is broad. No terminal spathillæ.

_Dimensions._--Length of the tube 1.5 to 2.0, breadth 0.03; branches 0.07 to 0.1.

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

4. _Auloceros cervinus_, n. sp. (Pl. 102, figs. 9, 10).

Radial tubes slender, spindle-shaped, slightly curved, tapering gradually from the middle towards the two ends. Terminal branches constantly three, obliquely ascending, each twice or three times forked (often more or less irregularly), with slender, curved, secondary and tertiary branches (twenty to twenty-four on each tube); the latter are scarcely half as broad as the three main branches of each tube. No terminal spathillæ.

_Dimensions._--Length of the tubes 2.0 to 3.5, breadth 0.03 to 0.04; branches 0.12 to 0.15 long.

_Habitat._--South Atlantic, Station 325, depth 2650 fathoms.

5. _Auloceros elegans_, n. sp. (Pl. 102, fig. 1).

Radial tubes slender, cylindrical, straight, equally broad. Terminal branches two or three, more or less irregularly branched, each with twelve to eighteen curved and pointed secondary branches. No terminal spathillæ. Differs from the preceding _Auloceros cervinus_ in the cylindrical form of the thinner straight tubes, and the more irregular ramification; the branches are nearly {1585}tangentially expanded, The specimen figured, with expanded pseudopodia, red central capsule, and green phæodium, was observed living by me in 1882 in Ceylon.

_Dimensions._--length of the tubes 1.0 to 2.0, breadth 0.02 to 0.03; branches 0.15 to 0.3.

_Habitat._--Indian Ocean, Ceylon (south of Matura), Haeckel, surface.

Subgenus 2. _Auloceratium_, Haeckel.

_Definition._--Distal ends of the terminal branches with a spathilla, or a small corona of radial, usually recurved teeth.

6. _Auloceros dicranaster_, n. sp. (Pl. 105, figs. 14, 15).

Radial tubes cylindrical, straight, equally broad. Terminal branches tangential, forked, expanded horizontally, five to six times as long as the tube is broad; their number is usually five (more rarely four or six), and each is divided into two short, equal, divergent, secondary branches, armed at the distal end with a spathilla of five or six unequal recurved teeth.

_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.01 to 0.02; branches 0.05 to 0.08.

_Habitat._--North Pacific, Stations 244 to 252, depth 2050 to 3050 fathoms.

7. _Auloceros spathillaster_, n. sp. (Pl. 102, fig. 12).

Radial tubes club-shaped or nearly cylindrical, straight, often thickened towards the distal end. Terminal branches ascending, three to six, usually four, partly simple, partly forked, slightly curved. The branches are from twice to three times as long as the tube is broad, and much thinner; at the distal end they are armed with a spathilla of five or six recurved teeth.

_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.02 to 0.03; branches 0.08 to 0.12.

_Habitat._--South Atlantic, Station 319, depth 2425 fathoms.

8. _Auloceros arborescens_, n. sp, (Pl. 102, figs. 11, 13).

Radial tubes club-shaped, irregularly curved, thickened towards the distal end. Terminal branches two opposite (rarely three or four), forked near the base, and either dichotomously or more irregularly branched; each tube bears fifteen to thirty, usually twenty to twenty-four, secondary branches, which are irregularly curved, and armed at the distal end with a spathilla of four to eight recurved teeth. The tubes are more richly branched than in the preceding, smaller, closely allied species, and the branches are more flatly expanded.

_Dimensions._--Length of the tubes 2.6 to 3.3, breadth 0.03 to 0.04; branches 0.1 to 0.2.

_Habitat._--South Pacific, Stations 288 to 295, depth 1500 to 3000 fathoms.

{1586}Genus 669. _Aulospathis_,[287] n. gen.

_Definition._--#Aulacanthida# with a veil of tangential needles, and with radial tubes, which bear two verticils of branches, a distal verticil of terminal branches, and a proximal verticil of lateral branches.

The genus _Aulospathis_ and the following _Aulodendron_ differ from the preceding Aulacanthida in the possession of lateral branches; these are usually similar to the terminal branches, and irregularly scattered along the distal half of the tubes in _Aulodendron_. In _Aulospathis_, however, the largest form in the family, each tube bears two whorls or verticils only, a verticil of terminal branches at the distal end, and a verticil of lateral branches beyond the latter, between the middle and distal third of the tube. The number of branches in each verticil is usually from two to four, rarely more; it is, however, very variable, so that the ten species described in the sequel are "Darwinian species," derived either from _Aulospathis polymorpha_, or from _Aulospathis variabilis_. Each branch bears at the distal end a spathilla, the teeth of which are very variable in form, number and arrangement.

Subgenus 1. _Aulospathessa_, Haeckel.

_Definition._--Distal ends of the radial tubes inflated, usually in the form of an ovate or pyriform terminal knob.

1. _Aulospathis bifurca_, n. sp. (Pl. 104, figs. 1-5).

Radial tubes with an inflated ovate terminal knob at the distal end, which bears two divergent, curved, terminal branches (often a few tubes bear three or four branches instead of the usual two). Proximal whorl usually cruciate, with four irregularly crossed lateral branches (but often with five or six, more rarely with two or three).

_Dimensions._--Length of the tubes 0.15 to 25 mm., breadth 0.04 to 0.06; branches 0.1 to 0.15.

_Habitat._--South Pacific, Stations 293 to 295, depth 1500 to 2270 fathoms.

2. _Aulospathis trifurca_, n. sp. (Pl. 104, figs. 6, 7, 7_a_).

Radial tubes with an inflated ovate terminal knob at the distal end, which bears three divergent, straight, or slightly curved terminal branches (often a few tubes bear two or four branches instead of the usual three). Proximal whorl irregular, usually with six divergent, straight, lateral branches.

_Dimensions._--Length of the tubes 2.2 to 3.4, breadth 0.03 to 0.05; branches 0.1 to 0.15.

_Habitat._--South Pacific (off Valparaiso), Stations 298 to 300, depth 1375 to 2225 fathoms.

{1587}3. _Aulospathis quadrifurca_, n. sp.

Radial tubes with an inflated ovate terminal knob at the distal end, which bears four crossed, divergent, curved terminal branches. Proximal whorl also rather regular, with a cross of four straight lateral branches.

_Dimensions._--Length of the tubes 3.0 to 4.0, breadth 0.04 to 0.08; branches 0.2 to 0.3.

_Habitat._--South Pacific, Station 291, depth 2250 fathoms.

4. _Aulospathis polymorpha_, n. sp. (Pl. 104, figs. 10-13).

Radial tubes with an inflated ovate terminal knob at the distal end, which bears a variable number of divergent, curved, irregular, terminal branches. Usually the majority of the tubes bear three branches, whilst others exhibit two or four, sometimes also five or six. Proximal whorl also very variable and irregular, with two to six, usually three or four unequal branches.

_Dimensions._--Length of the tubes 2.0 to 4.0, breadth 0.04 to 0.06; branches 0.1 to 0.3.

_Habitat._--South Pacific, Station 289, depth 2550 fathoms.

Subgenus 2. _Aulospathilla_, Haeckel.

_Definition._--Distal ends of the radial tubes of equal breadth or tapering gradually, not inflated, without terminal knobs.

5. _Aulospathis diodon_, n. sp.

Radial tubes without inflated terminal knob, forked at the tapering distal end, with two divergent curved branches of equal size. Proximal whorl cruciate, with four rather equal, crossed, straight, lateral branches (sometimes three or five instead of four in single tubes).

_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.04; branches 0.1 to 0.3.

_Habitat._--North Pacific, Station 231, depth 2250 fathoms.

6. _Aulospathis triodon_, n. sp. (Pl. 104, fig. 8).

Radial tubes without inflated terminal knob, with three divergent, slightly curved, terminal branches. Proximal whorl with a variable number of curved lateral branches, usually also three (often two or four, rarely more).

_Dimensions._--Length of the tubes 2 to 3, breadth 0.03 to 0.05; branches 0.2 to 0.3.

_Habitat._--North Pacific, Stations 250 to 253, depth 2740 to 3125 fathoms.

{1588}7. _Aulospathis tetrodon_, n. sp. (Pl. 104, fig. 9).

Radial tubes without inflated terminal knob, with four crossed, divergent, slightly curved terminal branches. Proximal whorl usually with an irregular cross of four lateral branches (often five or six, rarely two or three instead of the usual four).

_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.04; branches 0.2 to 0.3.

_Habitat._--North Pacific, Stations 244 to 245, depth 2775 to 2900 fathoms.

8. _Aulospathis hexodon_, n. sp.

Radial tubes without inflated terminal knob, with three forked, curved branches at the distal end, so that each tube usually bears six terminal branches; but other tubes of the same specimen bear only three simple or a few irregularly forked branches. Proximal whorl usually with six curved, irregular, lateral branches.

_Dimensions._--Length of the tubes 2.0 to 3.0, breadth 0.03 to 0.06; branches 0.2 to 0.5.

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

9. _Aulospathis furcata_, n. sp.

Radial tubes without inflated terminal knob, with a variable number of unequal terminal branches, which are partly simple, partly irregularly forked or branched; the usual number of terminal branches is three or four, more rarely two or five or six. Proximal whorl very irregular, usually with four to six unequal, lateral branches.

_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.05; branches 0.1 to 0.3.

_Habitat._--Stations 265 to 268, depth 2700 to 2900 fathoms.

10. _Aulospathis variabilis_, n. sp. (Pl. 104, figs. 14-17).

Radial tubes without inflated terminal knob, with a variable number of unequal terminal branches, which are constantly simple, never forked; the usual number is in the majority of the tubes three or four, often also two, rarely five to eight. Proximal whorl irregular, with a variable number of lateral branches (usually four to six).

_Dimensions._--Length of the tubes 2.0 to 3.0, breadth 0.03 to 0.06; branches 0.1 to 0.3.

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

Genus 670. _Aulodendron_,[288] n. gen.

_Definition._--#Aulacanthida# with a veil of tangential needles, and with radial tubes, which bear numerous, irregularly scattered, lateral and terminal branches.

{1589}The genus _Aulodendron_ differs from the other Aulacanthida in the possession of lateral and terminal branches, which are irregularly scattered on the radial tubes and not arranged in regular verticils. The branches are usually short, simple or forked, rarely longer and again irregularly ramified.

1. _Aulodendron antarcticum_, n. sp. (Pl. 105, fig. 5).

Radial tubes cylindrical, more or less curved, in the inner proximal half smooth and half as broad as in the outer distal half, which is studded with irregularly curved, partly branched spines, arising usually perpendicularly from the tube. The majority of the spines usually simple, the minority forked, with two to four short branches, the largest spines scarcely twice as long as the breadth of the tube.

_Dimensions._--Length of the tubes 0.7 to 0.9, breadth 0.01 to 0.02; length of the branches 0.02 to 0.04.

_Habitat._--Antarctic Ocean (Kerguelen), Stations 156 to 159, surface.

2. _Aulodendron pacificum_, n. sp. (Pl. 105, fig. 2).

Radial tubes cylindrical, slightly curved, in the proximal half smooth, in the distal half with scattered lateral branches, which are partly simple, partly forked, about twice as long as the breadth of the tube, and bear at the distal end a spathilla with five to six recurved teeth. The distal end of the tubes bears a spherical knob, which is separated by a deep stricture and armed with a bunch of six to twelve strong conical teeth.

_Dimensions._--Length of the tubes 1 to 1.2, breadth 0.015 to 0.02; branches 0.03 to 0.04.

_Habitat._--South Pacific, Station 293, depth 2025 fathoms.

3. _Aulodendron australe_, n. sp. (Pl. 105, fig. 3).

Radial tubes cylindrical, straight, thin, smooth in the proximal half, armed with numerous lateral branches in the distal half; the majority of the branches forked, about as long as the breadth of the tube, with two or three short ramules, each of which bears a spinulate terminal knob. The distal end of the tubes also forked, with two or three divergent branches.

_Dimensions._--Length of the tubes 1.2 to 1.6, breadth 0.01 to 0.012.

_Habitat._--South Pacific, Station 289; New Zealand, Station 169, surface.

4. _Aulodendron atlanticum_, n. sp.

Radial tubes cylindrical, tapering gradually towards the two ends; smooth and straight in the proximal half, irregularly curved and branched in the distal half, with ten to twenty (rarely more) branches, which arise almost perpendicularly from the tube. The proximal branches are from four to eight times as long as the greatest breadth of the tube, forked, with two or three short ramules; {1590}the distal branches are much smaller and simple. The distal end of each branch bears a spathilla with four to six short teeth.

_Dimensions._--Length of the tubes 2.4 to 3.6, breadth 0.06 to 0.08.

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

5. _Aulodendron indicum_, n. sp. (Pl. 105, fig. 1).

Radial tubes cylindrical, irregularly curved, tapering gradually towards the two ends; smooth in the proximal half, irregularly branched in the distal half, with ten to twenty or more curved branches. The proximal branches are very large, one-sixth to one-fourth as long as the tube and irregularly ramified; the distal branches are much shorter, also ramified or simple. All the branches are more or less curved and bear a spinulate knob at the distal end.

_Dimensions._--Length of the tubes 1.2 to 1.8, breadth 0.02 to 0.03; length of the branches 0.1 to 0.3.

_Habitat._--Indian Ocean; Cocos Islands (Rabbe), surface.

----

Order II. PHÆOSPHÆRIA, Haeckel, 1879.

_Definition._--PHÆODARIA with a simple or double, usually spherical lattice-shell, which is not bivalved and has no peculiar mouth or peristome. Central capsule placed in the centre of the shell.

Family LXXIV. #OROSPHÆRIDA#, n. fam. (Pls. 106, 107).

_Definition._--PHÆODARIA with a big spherical (sometimes polyhedral or ellipsoidal), very coarse shell, which is composed of thick bars containing an axial canal. Nodal points of the coarse network without astral septa. Meshes of moderate size, irregularly polygonal. Surface of the shell usually with radial spines and pyramidal elevations. No peculiar mouth in the shell. Central capsule tripylean, in the centre of the shell.