Dimensions.—Length of the shell (with sixteen joints) 0.3, basal breadth 0.12. Length of each single joint (on an average), 0.02.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

7. Artopilium stichopterygium, n. sp. (Pl. 75, fig. 8).

Shell slenderly ovate, subconical, with five deep strictures. The four lower joints are nearly equal in length, each about twice as long as each of the first two joints. The fourth and fifth joints are the broadest. Along the whole shell arise three broad, triangular wings, which envelop the long, slender, pyramidal horn of the cephalis. In the delicate and loose lattice-work of each wing is a longitudinal series of six large, ovate apertures, one on each joint. The small pores of the shell are irregular, polygonal, or roundish.

Dimensions.—Length of the shell (with six joints) 0.17, breadth 0.08. Length of each of the four lower joints 0.03, of each of the two upper joints 0.015.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

8. Artopilium anomalum, Haeckel.

Shell five-jointed, with four internal septa, of a peculiar, irregular, and abnormal form. Cephalis small, hemispherical, with an oblique, curved horn. Thorax inflated, campanulate, with three large, latticed, and carinated protuberances. The third joint (the first abdominal joint) nearly as large as the thorax, two to three times as long as the two last joints, the septa of which are connected in a peculiar manner by a common nodal point on one side. Pores subregular, circular. (Compare the detailed description of this remarkable species—perhaps the type of a peculiar genus, Stichopterygium—in my Monograph, loc. cit.)

Dimensions.—Length of the shell (with five joints) 0.15, breadth 0.1.

Habitat.—Mediterranean (Messina), surface.

Genus 628. Pteropilium,^[245] n. gen.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta) with three latticed external ribs or wings, without terminal feet. No horn upon the cephalis.

The genus Pteropilium (confounded by Ehrenberg with Pterocanium) differs from this three-jointed form by addition of new terminal joints. The shell-form is in general the same as in the preceding species, from which it may be derived by phylogenetic loss of the cephalic horn.

1. Pteropilium sphinx, Haeckel.

Shell slenderly conical, with three slight strictures. Each of the two last joints as long as the two first joints together. Cephalis hemispherical. Third joint with three prominent, divergent ribs, which are prolonged along the fourth joint into three latticed, triangular wings, ending in a free, strong, conical spine. Pores subregular, circular, twice as broad in the fourth joint as in the third, and three times as broad as in the second joint.

Dimensions.—Length of the shell (with four joints) 0.15, of the single joints, a 0.02, b 0.03, c 0.05, d 0.05; breadth of the third joint 0.09, of the fourth joint 0.06.

Habitat.—Fossil in Barbados.

2. Pteropilium bombus, Haeckel.

Shell broadly conical, with three deep strictures. Length and breadth of the four joints, gradually increasing giving the proportion 2 : 4 : 5 : 6. Cephalis hemispherical, second joint with three prominent ribs, which are prolonged along the third and fourth joints into three slender, triangular pointed wings, with few pores at the base. Pores of the shell subregular, circular.

Dimensions.—Length of the shell (with four joints) 0.17, of the single joints, a 0.02, b 0.04, c 0.05, d 0.06; basal breadth 0.11.

Habitat.—Fossil in Barbados.

3. Pteropilium pyramis, n. sp.

Shell three-sided, pyramidal, with five deep strictures. Length and breadth of the six joints gradually increasing towards the wide mouth. Cephalis subconical. Along the four first joints arise three slender, divergent ribs, which at the fifth joint become three free, triangular, latticed wings, with long, descending, terminal spines. The sixth joint is free, without wings. Pores irregular, roundish.

Dimensions.—Length of the shell (with six joints) 0.2, basal breadth 0.2.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Genus 629. Stichocampe,^[246] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta) with three solid lateral ribs or wings, which are prolonged into three solid terminal feet. Cephalis with a horn.

The genus Stichocampe, together with the three following genera, represent a peculiar small group among the Stichocyrtida, differing from all other members of this family in the possession of three free terminal feet around the open mouth. In the two genera, Stichocampe and Stichopterium, these three feet are the terminal prolongations of three lateral ribs or crests, while in the two genera developed later, Podocampe and Stichopodium, the three original ribs are lost, and only the three free feet remain. Stichocampe (the most primitive of these four genera) may be derived from Theopodium by addition of new joints.

1. Stichocampe divergens, n. sp.

Shell spiny, broadly pyramidal, with six deep strictures. Seven joints gradually increasing in breadth and length, the seventh twice as broad as the fourth. Pores subregular, circular, hexagonally framed. The prominent edges of the pyramis are prolonged over the wide mouth into three slender, straight, divergent feet, half as long as the shell.

Dimensions.—Length of the shell (with seven joints) 0.3, of the last joint 0.06, of the fourth 0.03; breadth 0.25.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

2. Stichocampe convergens, n. sp.

Shell smooth, slenderly pyramidal, with eight distinct strictures. All nine joints nearly equal in length. Pores regular, circular, forming three or four transverse rows in each joint. The smooth edges of the pyramis are prolonged over the wide mouth into three slender, slightly curved, and convergent feet, twice as long as one joint.

Dimensions.—Length of the shell (with nine joints) 0.25, of each joint, about 0.035; breadth 0.11.

Habitat.—Central Pacific, Station 273, depth 2350 fathoms.

Genus 630. Stichopterium,^[247] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta), with three lateral ribs or wings, which are prolonged into three latticed, terminal feet. Cephalis with a horn.

The genus Stichopterium has in general the same shell-formation as the nearly allied Stichocampe, but differs from this ancestral form in the fenestration of the three terminal feet. It corresponds, therefore, to Pterocanium among the Tricyrtida.

1. Stichopterium pterocanium, n. sp.

Shell campanulate, with three distinct strictures. Length of the four joints = 2 : 3 : 4 : 3. Cephalis subspherical, with a conical horn of twice the length. Pores regular, hexagonal, with thin bars. From the collar stricture arise three divergent ribs, which in the fourth joint become latticed and prolonged over its mouth into three slender, pyramidal, latticed, divergent feet, nearly as long as the shell. (Similar to Pterocanium bicorne, Pl. 73, fig. 5, but with four distinct strictures.)

Dimensions.—Length of the shell (with four joints) 0.12, breadth 0.1. Length of the single joints, a 0.02, b 0.03, c 0.04, d 0.03.

Habitat.—South Pacific (off Patagonia), Station 304, surface.

2. Stichopterium virgineum, n. sp.

Shell three-sided, pyramidal, with four sharp strictures. Length of the five joints = 1 : 4 : 3 : 2 : 1. Cephalis hemispherical, with a pyramidal horn three times the length. Pores subregular, circular, in the second campanulate joint twice or three times as broad as in the four other joints. From the base of the cephalic horn arise three divergent ribs, which descend over the whole shell, and in the fourth joint become latticed and prolonged over the wide mouth of the fifth joint into three latticed, pyramidal feet, as long as the second joint. (Similar in general form to Pterocanium virgineum, Pl. 73, fig. 6.)

Dimensions.—Length of the shell (with five joints) 0.22, breadth 0.16. Length of the single joints, a 0.02, b 0.08, c 0.06, d 0.04, e 0.02.

Habitat.—Central Pacific, Station 281, surface.

3. Stichopterium dictyopodium, n. sp.

Shell subovate, with five internal annular septa. The third and the fourth joints are about twice as long as the two first and the two last joints. The fifth joint is the broadest. Pores small and numerous, regular, circular. The three first joints are without ribs. From the third stricture arise three divergent, triangular, latticed wings, which descend along the three last joints, and are prolonged over the wide mouth as three slender, fenestrated, divergent feet, two-thirds as long as the shell.

Dimensions.—Length of the shell (with six joints) 0.18, breadth 0.12. Length of the two middle joints 0.04, of the four others 0.02 to 0.03.

Habitat.—South Pacific, Station 288, surface.

Genus 631. Podocampe,^[248] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta), without lateral ribs or wings, but with three free, solid, terminal feet. Cephalis with a horn.

The genus Podocampe is next allied to Stichocampe, and has also three solid, free feet around the mouth, but it has lost the three lateral ribs of the latter. It corresponds to Podocyrtis among the Tricyrtida, and may be derived from this by addition of new terminal joints.

1. Podocampe tripodiscus, n. sp.

Shell ovate, with three annular septa. The fourth joint is the broadest, and as long as the three other joints together. Cephalis hemispherical, with a pyramidal horn of twice the length. Mouth constricted, with three convergent, curved, triangular feet, half as long as the last joint. Pores subregular, circular. (Similar to Podocyrtis pedicellaria, Pl. 72, fig. 8, but larger, with more slender feet, and four joints instead of three.)

Dimensions.—Length of the shell (with four joints) 0.2, of the last joint 0.1; breadth 0.12.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

2. Podocampe trictenota, n. sp. (Pl. 97, fig. 15).

Shell slenderly ovate, nearly spindle-shaped, with three annular septa. The third joint is the broadest, somewhat longer than the second and third joints, and three times as long as the hemispherical cephalis, which bears a strong pyramidal horn of twice the length. Along the two first joints arise three divergent, dentate crests, each with four to six strong pyramidal teeth. Mouth strongly constricted, only as broad as the cephalis, with three conical, vertical, parallel feet, as long as the cephalis. Pores regular, circular, hexagonally framed.

Dimensions.—Length of the shell (with four joints) 0.14, of the third joint 0.06, of the last 0.04; breadth 0.08.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

3. Podocampe conica, n. sp.

Shell conical, with five distinct strictures. Six joints gradually increasing in length and breadth. The sixth joint is the broadest, and twice as long as the fifth joint, three times as long as the fourth. Cephalis conical, with a stout, conical horn of the same length. Mouth little constricted, with three divergent, conical feet, half as long as the shell. Pores subregular, circular. (Similar to Podocyrtis lithoconus, Pl. 72, fig. 3, but with six joints instead of three, and with divergent, slender feet.)

Dimensions.—Length of the shell (with six joints) 0.18, of the last joint 0.06; breadth 0.12.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

4. Podocampe cornuta, n. sp.

Shell slenderly conical, with seven distinct strictures. Eight joints of nearly equal length, gradually increasing in breadth. Along the three last joints arise three prominent crests, which are prolonged over the wide mouth into three divergent, conical feet, half as long as the shell. Cephalis hemispherical, with a conical, slender, curved horn, three times the length. Pores subregular, hexagonal.

Dimensions.—Length of the shell (with eight joints) 0.16, of each single joint (on an average) 0.02; basal breadth 0.07.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

Genus 632. Stichopodium,^[249] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta) without lateral ribs or wings, but with three free latticed terminal feet. Cephalis with a horn.

The genus Stichopodium differs from the preceding genus Podocampe in the fenestration of the three free terminal feet. It agrees in this character with the genus Stichopterium, and may be derived either from this by loss of the lateral ribs, or from the three-jointed Pterocanium by addition of new shell-joints.

1. Stichopodium dictyopodium, n. sp. (Pl. 75, fig. 6).

Shell subcylindrical, in the upper third conical, with six or seven internal annular septa. All seven or eight joints are about equal in length, except the small hemispherical cephalis, which is scarcely half as long, and bears an oblique, conical horn of the same length. Pores small and numerous, regular, circular, quincuncial. The last joint with wide open mouth, and a peristome of three large, triangular, latticed, shovel-shaped, vertical feet.

Dimensions.—Length of the shell (with seven joints) 0.2, breadth 0.11. Length of each single joint about 0.03, of the feet 0.03.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

Subfamily 2. Stichoperida, Haeckel, Prodromus, p. 439.

Definition.—Podocampida with the terminal mouth of the shell fenestrated (vel Stichocyrtida triradiata clausa).

Genus 633. Stichopera,^[250] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichoperida (vel Stichocyrtida triradiata clausa) with three solid lateral ribs, or three longitudinal combs of spines. Cephalis with a horn.

The genus Stichopera, and the two following genera, represent the small subfamily of Stichoperida, or those triradiate Stichocyrtida in which the terminal mouth is closed by lattice-work. In Stichopera the three radial appendages are either solid lateral ribs or longitudinal combs of spines; the closed basal part of the shell is rounded, not pointed. It may be derived either from Stichopilium by closure of the mouth, or from Lithornithium by increase of the number of the joints.

Subgenus 1. Stichoperina, Haeckel.

Definition.—Shell with three solid radial ribs, or longitudinal dentate crests.

1. Stichopera ovata, n. sp.

Shell ovate, with three distinct strictures. Length of the four joints = 2 : 3 : 4 : 6. The fourth joint is the broadest, and twice as long as the second, with hemispherical basal pole. Cephalis hemispherical, with a conical horn of twice the length. Along the second and third joints descend three prominent divergent ribs, which disappear in the middle zone of the fourth joint. Pores regular, circular.

Dimensions.—Length of the shell (with four joints) 0.15, breadth 0.1. Length of the single joint, a 0.02, b 0.03, c 0.04, d 0.06.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

2. Stichopera lagena, n. sp.

Shell bottle-shaped, with six sharp strictures; the upper half is slender, conical, and composed of six joints of nearly equal length, the lower half is formed only by the last subspherical joint. Cephalis subspherical, with a pyramidal horn of the same length. From its base arise three divergent ribs, which attain the greatest height in the fourth joint, and disappear in the sixth joint. (Similar to Stichophæna ritteriana, Pl. 75, fig. 12, but only with three ribs and seven joints.) Pores regular, hexagonal.

Dimensions.—Length of the shell (with seven joints) 0.25. Length of each joint 0.02 to 0.025, of the last joint 0.12; breadth 0.14.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

3. Stichopera serrata, n. sp.

Shell bottle-shaped, with eight deep strictures. The first eight joints are little different in length, and form together a slender cone, while the last joint is four times as long (half as long as this cone), and subspherical. Cephalis conical, with a slender, prismatic horn of three times the length. Along the whole shell arise three divergent, serrate ribs, which disappear towards the hemispherical, basal pole. Pores subregular, hexagonal.

Dimensions.—Length of the shell (with nine joints) 0.21, breadth 0.08; length of each joint 0.016 to 0.019, of the last joint 0.07.

Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.

Subgenus 2. Sticholagena, Haeckel.

Definition.—Shell with three radial combs or longitudinal rows of isolated spines (instead of the three radial ribs).

4. Stichopera pectinata, n. sp. (Pl. 75, fig. 11).

Shell club-shaped, with nine sharp strictures. The nine upper joints increase gradually in length and breadth, and are together three times as long as the inflated, inversely campanulate and rounded last joint. Each joint (excepting the first and the last) bears three thin, bristle-shaped spines, which are directed obliquely upwards. Cephalis subspherical, with a slender, conical horn of twice the length. Pores subregular, in the upper half circular, in the lower hexagonal.

Dimensions.—Length of the shell (with ten joints) 0.22, breadth 0.09; length of the eighth and ninth joints 0.02, of the last joint 0.075.

Habitat.—North Pacific, Station 241, depth 2300 fathoms.

5. Stichopera clavata, n. sp.

Shell club-shaped, with eight sharp strictures, very similar in form and structure to that of the preceding species, but differing from it in the club-like form of the inflated last joint, which is nearly half as long as the shell; its lower half is broader than the upper (the reverse being the case in the preceding species). The lateral spines of the three combs are not directed upwards, but downwards. Cephalis with a curved, conical horn of the same length.

Dimensions.—Length of the shell (with nine joints) 0.2, breadth 0.08; length of the eighth joint 0.02, of the last joint 0.09.

Habitat.—South Pacific, Station 298, depth 2225 fathoms.

6. Stichopera verticillata, n. sp.

Shell club-shaped, with ten sharp strictures, similar in form and structure to that of the two preceding species, but differing from them in the ovate form of the slender last joint, which is one-third as long as the whole shell, and five times as long as the preceding joint. The lateral spines of the three combs are directed nearly horizontally, and are much more numerous, each joint (excepting the first and last) bears six to twelve spines (two, three, or four in each radius). They form together about thirty horizontal verticils, each with three spines. Cephalis with a curved, conical horn of three times the length.

Dimensions.—Length of the shell (with eleven joints) 0.28, breadth 0.09; length of the tenth joint 0.02, of the last joint 0.1.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Genus 634. Cyrtopera,^[251] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichoperida (vel Stichocyrtida triradiata clausa) with three latticed lateral wings, or three longitudinal rows of lattice wings. Cephalis with a horn.

The genus Cyrtopera differs from the preceding Stichopera in the fenestration of the three lateral wings, and bears therefore to it the same relation that Sethornithium exhibits to Lithornithium among the Tricyrtida.

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

Definition.—Shell with three annular strictures and four joints.

1. Cyrtopera thoracoptera, n. sp. (Pl. 75, fig. 3).

Shell inflated, with three very deep strictures. Length of the four joints = 2 : 7 : 8 : 6. Cephalis hemispherical, with a slender, prismatic horn, half as long as the shell. Thorax subspherical, in its middle third with three latticed, triangular wings of half the length. Abdomen with inflated third, and inversely hemispherical fourth joint; the third is the broadest. Pores subregular, hexagonal, with thin bars.

Dimensions.—Length of the shell (with four joints) 0.23. Breadth of the third (broadest) joint 0.13. Length of the single joints, a 0.02, b 0.07, c 0.08, d 0.06.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

2. Cyrtopera ornithoptera, n. sp.

Shell broadly ovate, with three slight strictures. Length of the four joints = 1 : 2 : 3 : 4. Cephalis hemispherical, with a slender, pyramidal horn of three times the length. Along the second and third joints arise with broad base three latticed, triangular wings, nearly as long as the whole shell. Abdomen inflated. The fourth joint is the broadest and longest, with hemispherical basal pole. Pores subregular, hexagonal. (Similar to Artopilium longicorne, Pl. 77, fig. 10, but with more closely reticulated network, and perfectly closed mouth.)

Dimensions.—Length of the shell (with four joints) 0.2. Breadth of the fourth (broadest) joint 0.14. Length of the single joints, a 0.02, b 0.04, c 0.06, d 0.08.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.

3. Cyrtopera gasteroptera, n. sp.

Shell slenderly ovate, with three distinct strictures. Length of the four joints = 2 : 6 : 7 : 6. Cephalis subspherical, with a stout pyramidal horn of the same length. The three following joints have nearly equal length; the third is the broadest. The thorax exhibits three divergent solid ribs; as prolongations of these, three descending latticed wings, of about the same length, arise from the third joint, with broad triangular base. The fourth joint is inversely conical, blunt. Pores irregular, roundish. (Similar to Hexalatractus fusiformis, Pl. 68, fig. 13, but with three wings and four joints.)

Dimensions.—Length of the shell (with four joints) 0.21. Breadth of the third (broadest) joint 0.11. Length of the single joints, a 0.02, b 0.06, c 0.07, d 0.06.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

Subgenus 2. Cyrtolagena, Haeckel, 1879, Atlas (Pl. 75).

Definition.—Shell with four or more annular strictures, and five or more joints.

4. Cyrtopera laguncula, n. sp. (Pl. 75, fig. 10).

Shell bottle-shaped, with seven sharp strictures; the upper part is slender, conical, composed of seven joints of nearly equal length; the lower part is only formed by the spherical last joint. Cephalis subspherical, with a slender curved horn at three times the length. Along the whole shell arise three longitudinal combs or rows of ascending spines (three on each joint, fifteen on the last). These are connected by three divergent longitudinal rods, so that three elegant fenestrated ribs are formed (each rib with one series of large square meshes). Pores in the seven upper joints regular, circular, in the last polygonal, irregular and larger.

Dimensions.—Length of the shell (with eight joints) 0.17, of the last joint 0.08; breadth 0.08.

Habitat.—South Pacific, Station 298, depth 2225 fathoms.

5. Cyrtopera lagenella, n. sp.

Shell bottle-shaped, with twelve sharp strictures, very similar in form and structure to the preceding species; but instead of the three simple fenestrated ribs there arise here, along the shell, three series of short, triangular, latticed wings. The four first and the last joints are without wings. The hemispherical cephalis bears a curved conical horn, as long as the subspherical last joint. The twelve joints of the upper conical part are nearly equal in length, with regular, small, hexagonal pores. The last inflated joint is one-third as long as the shell, and has larger, irregular, polygonal pores.

Dimensions.—Length of the shell (with thirteen joints) 0.25, of the last joint 0.08; breadth 0.1.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

Genus 635. Artopera,^[252] Haeckel, 1881, Prodromus, p. 438.

Definition.—Stichoperida with three solid lateral ribs or wings, and with a vertical basal spine on the end of the pointed last joint. Cephalis with a horn.

The genus Artopera differs from its ancestral genus, Stichopera, in the development of a vertical terminal spine on the end of the last joint, and bears therefore to it the same relation that Rhopalatractus exhibits to Rhopalocanium among the Tricyrtida.

1. Artopera loxia, Haeckel.

Shell spindle-shaped, with three deep strictures. Length of the four joints = 2 : 5 : 5 : 4. Cephalis subspherical, hyaline, without pores, with a thick conical horn of the same length. From the two following joints, which are nearly equal in size and of campanulate form, arise, with broad base, three divergent, slender, triangular wings. The fourth joint is smaller, inversely conical, and bears on the basal pole a strong, three-sided pyramidal, vertical spine, half as long as the shell. Pores subregular, circular.

Dimensions.—Length of the shell (with four joints) 0.18, breadth 0.07. Length of the single joints, a 0.02, b 0.055, c 0.055, d 0.05.

Habitat.—Fossil in Barbados.

2. Artopera motacilla, n. sp.

Shell spindle-shaped, with three distinct strictures. Length of the four joints = 1 : 2 : 3 : 2. Cephalis subspherical, with a conical horn of twice the length. From the second joint arise three longitudinal, smooth, divergent ribs, which are prolonged over the third joint, and terminate at the third stricture in three short, conical teeth. The fourth is inversely conical, and bears on the basal pole a strong, vertical, cylindrical spine, nearly half as long as the shell. Pores subregular, circular, hexagonally framed. (Similar to Rhopalatractus pentacanthus, Pl. 68, fig. 11, but differing in the presence of three sharp strictures, and a large, conical, basal joint).

Dimensions.—Length of the shell (with four joints) 0.18. Breadth of third (broadest) joint 0.09. Length of the single joint, a 0.02, b 0.04, c 0.06, d 0.04.

Habitat.—Western Tropical Pacific (Philippine Sea), Station 198, depth 2150 fathoms.

3. Artopera fusiformis, n. sp.

Shell spindle-shaped, with three distinct strictures. Length of the four joints = 2 : 3 : 5 : 5. Cephalis conical, with a strong, conical horn of the same length. Along the three first joints arise three divergent, irregularly dentate ribs, which at the second joint bear stronger, pyramidal teeth, also at the third stricture a strong, terminal tooth. Fourth joint without ribs, inversely conical, with a strong, conical, terminal spine of half the length on the basal pole. Pores subregular, circular, double-edged.

Dimensions.—Length of the shell (with four joints) 0.15. Breadth of the third (broadest) joint 0.08. Length of the single joint, a 0.02, b 0.03, c 0.05, d 0.05.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

Family LXIX. Phormocampida, n. fam.

Definition.—Stichocyrtida multiradiata. (Cyrtoidea with an annulated shell, divided by three or more transverse constrictions into four or more annular joints, with numerous, four to nine or more, radial apophyses.)

The family Phormocampida comprises those Cyrtoidea in which the lattice-shell is composed of numerous (four to eight or more) annular joints, and bears numerous (four to eight or more) radial apophyses. We divide it into two subfamilies, differing in the shape of the terminal mouth. This is a simple wide opening in the Stichophormida (and the united Artophormida), closed by a lattice-plate in the Stichophænida (and the united Artophænida). The phylogenetic origin of the Phormocampida may be found in the Phormocyrtida.

Three fossil forms only of Phormocampida were hitherto known, two of which were described by Stöhr as Eucyrtidium acutatum and Lithocampe fimbriata, the third by Ehrenberg as Eucyrtidium barbadense; the latter belongs to Artophormis, the two former to Cyrtophormis. All the other Phormocampida here described, forming together thirty-one species, are new; twenty-two of them belong to the Stichophormida, and nine to the Stichophænida. The latter are disposed in two, the former in four genera.

The number of the radial apophyses is sometimes six or nine, sometimes twelve or more, usually a multiple of three. They are either lateral ribs or wings (Pl. 75, figs. 2, 5, 12), or terminal feet (Pl. 77, figs. 13 to 18). Usually they are solid, not latticed, and not strongly developed. The majority of Phormocampida have probably been derived from Phormocyrtida by growth of the abdomen, which becomes annulated by transverse constrictions. Some forms, however, may be derived from similar Podocampida, by interpolation of three to six or more secondary apophyses between the three primary or perradial apophyses.

Synopsis of the Genera of Phormocampida.

Subfamily 1. Stichophormida, Haeckel, 1881, Prodromus, p. 439.

Definition.—Phormocampida with the terminal mouth of the shell open (vel Stichocyrtida multiradiata aperta).

Genus 636. Stichophormis,^[253] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichophormida (vel Stichocyrtida multiradiata aperta) with conical or pyramidal shell, bearing in its wall numerous lateral ribs, which are prolonged into terminal feet. Mouth not constricted.

The genus Stichophormis and the three following genera represent together the subfamily of Stichophormida, or of those multiradiate Stichocyrtida in which the mouth remains open; they may be derived therefore either from the Theophormida by increasing the number of the shell-joints, or from the Stichopilida by the interpolation of new radial ribs between the three primary ribs. Stichophormis may have been derived in the former way from Theophormis.

Subgenus 1. Stichophormium, Haeckel.

Definition.—Shell with six prominent longitudinal ribs, which are prolonged into six (sometimes five or seven) divergent free feet over the mouth.

1. Stichophormis pyramidalis, n. sp.

Shell slenderly pyramidal, with three annular septa, and six prominent radial ribs, which arise from the collar-septum, and are prolonged on the mouth into six free, divergent, pyramidal feet, about as long as the shell. Length of the four joints = 2 : 3 : 5 : 8. Cephalis subspherical, with a stout, pyramidal horn of twice the length. Pores regular, circular.

Dimensions.—Length of the shell (with four joints) 0.18, basal breadth 0.08. Length of the single joints, a 0.02, b 0.03, c 0.05, d 0.08.

Habitat.—Central Pacific, Station 273, depth 2350 fathoms.

2. Stichophormis lucerna, n. sp.

Shell slenderly pyramidal, with three annular septa and six prominent radial ribs, which arise from the second stricture, and are prolonged over the mouth into six free, divergent, cylindrical feet, half as long as the shell. Length of the four joints = 1 : 2 : 3 : 15. Cephalis hemispherical, with a prismatic horn of the same length. Pores in the first and second joints very small and scarce, in the third campanulate joint circular, hexagonally framed, in the colossal fourth joint very large, polygonal (each about as large as the third joint).

Dimensions.—Length of the shell (with four joints) 0.4, basal breadth 0.2. Length of the single joints a 0.02, b 0.04, c 0.06, d 0.3.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

3. Stichophormis cornutella, n. sp. (Pl. 75, fig. 9).

Shell slenderly conical, with nine annular strictures and six longitudinal divergent ribs, which arise in the middle of the shell (from the sixth or seventh stricture), and are prolonged over the wide mouth into six slender bristle-shaped feet, about half as long as the shell. The bases of the feet are connected by arcades of lattice-work. All ten joints have nearly the same length and regular hexagonal pores (in the first and second joints circular). Cephalis hemispherical, with a very large curved horn, nearly half as long as the shell, and on one side decurrent to the fourth or fifth joint.

Dimensions.—Length of the shell (with ten joints) 0.16, of each single joint about 0.016; basal breadth 0.07.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

Subgenus 2. Stichophormiscus, Haeckel.

Definition.—Shell with nine prominent radial ribs, which are prolonged over the mouth into nine (sometimes eight or ten) divergent free feet.

4. Stichophormis novena, n. sp. (Pl. 79, fig. 9).

Shell slenderly conical, very similar to the preceding, but with eleven annular strictures and nine divergent ribs, which arise from the tenth or eleventh stricture, and are prolonged over the wide mouth into nine bristle-shaped feet, half as long as the shell. The length of the twelve joints increases gradually; the tenth is twice as long as the sixth. Pores regular, circular. Cephalis hemispherical, with a curved conical horn of twice the length. (In the somewhat mutilated specimen figured, the horn and the nine feet were broken off, but were well preserved in another specimen, found afterwards.)

Dimensions.—Length of the shell (with twelve joints) 0.22, eighth joint 0.02, fourth joint 0.01; basal breadth 0.12.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

5. Stichophormis radiata, n. sp.

Shell slender, conical, with fourteen annular strictures, and nine radial ribs; three primary ribs arise from the third stricture, the other six (secondary) ribs from the ninth stricture; all are prolonged over the mouth into nine slender bristle-shaped feet, about twice as long as one joint. All joints have nearly the same length. Cephalis subspherical, with a straight, conical horn three times the length. Pores regular, hexagonal.

Dimensions.—Length of the shell (with fifteen joints) 0.24, of each joint, about 0.016; basal breadth 0.12.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

Genus 637. Phormocampe,^[254] n. gen.

Definition.—Stichophormida (vel Stichocyrtida multiradiata aperta), with conical or pyramidal shell, without lateral ribs. Mouth dilated, with a corona of terminal feet.

The genus Phormocampe may be derived from the preceding Stichophormis by loss of the lateral ribs, whilst the terminal feet remain. It bears therefore to the latter the same relation that Calocyclas exhibits to Theophormis among the Tricyrtida.

Subgenus 1. Anthocorys, Haeckel, 1881, Prodromus, p. 437.

Definition.—Shell with three transverse strictures or annular septa, and with four distinct joints.

1. Phormocampe campanula, n. sp. (Pl. 77, fig. 13).