Shell nut-shaped, tuberculate, with a complete internal sagittal ring and numerous small circular pores. Basal plate with four larger central and a circle of twelve to twenty smaller peripheral pores. Apical horn half as long as the shell, bristle-shaped. Three primary feet longer and more deeply inserted than the three secondary feet; all six feet strongly divergent, bristle-shaped, shorter than the shell.

Dimensions.—Shell 0.06 long, 0.09 broad; horn 0.03 long; primary feet 0.05, secondary 0.02 long.

Habitat.—Fossil in Barbados.

3. Hexaspyris bütschlii, Haeckel.

Shell nut-shaped, spinulate, with a complete internal sagittal ring and subregular circular pores. Basal plate with twelve pores (four larger central and eight smaller peripheral). Apical horn stout, oblique, as long as the shell. Six feet of equal length, slightly divergent, nearly vertical, slender, three to four times as long as the shell.

Dimensions.—Shell 0.05 long, 0.07 broad; horn 0.06, feet 0.15 to 0.2 long.

Habitat.—Fossil in Barbados.

4. Hexaspyris spinosa, Haeckel.

Shell subspherical, smooth, with slight sagittal stricture and irregular polygonal pores; on each side of the stricture two pairs of larger pores. Basal plate with two large pores only. Apical horn short, pyramidal, three primary feet half as long as the shell and twice as long as the three secondary feet. All six feet pyramidal, slightly divergent.

Dimensions.—Shell 0.05 long, 0.07 broad; horn 0.02, feet 0.02 to 0.04 long.

Habitat.—Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta).

5. Hexaspyris ophirensis, Haeckel.

Shell nut-shaped, with deep sagittal stricture and numerous irregular roundish pores; two pairs of larger pores on each side of the stricture. Apical horn short, curved. Six feet equal, divergent, straight, slender, about as long as the shell.

Dimensions.—Shell 0.05 long, 0.1 broad; horn 0.01, feet 0.05 to 0.08 long.

Habitat.—Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen.

Subgenus 2. Hexacorethra, Haeckel.

Definition.—Feet forked or branched.

6. Hexaspyris hexacorethra, n. sp. (Pl. 95, fig. 8).

Shell campanulate, smooth, with sharp sagittal stricture and irregular roundish pores. Basal plate with six larger collar pores. Apical horn very long and thin, three-sided prismatic, straight, ten to twenty times as long as the shell, branched at the distal end. Six feet thinner, bristle-shaped, six to eight times as long as the shell, divergent, irregularly curved, in the distal part branched, besom-shaped; the sternal foot at its base with a large conical horizontal spur.

Dimensions.—Shell 0.034 diameter; horn 0.4 to 0.8 long, feet 0.2 to 0.3 long.

Habitat.—Central Pacific, Station 265, surface.

7. Hexaspyris articulata, Haeckel.

Shell nut-shaped, tuberculate, with deep sagittal stricture and small irregular roundish pores. Basal plate with six pores (?). Apical horn conical, longer than the shell. Six feet very large, thick cylindrical, divergent, three to four times as long as the shell, with few irregular lateral branches (often much more developed than in Ehrenberg's figure).

Dimensions.—Shell 0.036 long, 0.05 broad; horn 0.05, feet 0.1 to 0.15 long.

Habitat.—Fossil in Barbados.

Genus 454. Liriospyris,^[72] Haeckel, 1881, Prodromus, p. 443.

Definition.—Zygospyrida with six basal feet and three coryphal horns.

The genus Liriospyris differs from the preceding Hexaspyris, its ancestral form, in the possession of three coryphal horns (one odd apical in the middle, and two paired frontal horns on each side of it); it therefore bears to the latter the same relation that Triceraspyris does to Tripospyris.

1. Liriospyris hexapoda, n. sp. (Pl. 86, fig. 7).

Shell subspherical, smooth, with slight sagittal stricture and irregular roundish pores; two to three pairs of large annular pores on each side of the stricture. Basal plate with four large collar pores. Three horns and six feet nearly of the same size and of similar form, conical, divergent, about one-third as long as the shell.

Dimensions.—Shell diameter 0.09 to 0.1; horns and feet 0.03 to 0.04 long.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms.

2. Liriospyris clathrata, Haeckel.

Shell campanulate or nearly spherical, smooth, with slight sagittal stricture. Three pairs of large annular pores on each side of the stricture; a few smaller irregular pores on the lateral sides. Basal plate with six large collar pores (Bütschli, loc. cit., fig. 10a). Three horns and six feet nearly of the same size and form; short, conical, slightly divergent or nearly parallel, shorter than half the ring. (The size of the nine appendages is in this common species rather variable; sometimes they are rudimentary, at other times much stronger than in the good figure of Bütschli.)

Dimensions.—Shell diameter 0.08 to 0.09, horns and feet 0.01 to 0.03.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific; also fossil in Barbados and Sicily.

3. Liriospyris heteropoda, n. sp.

Shell nut-shaped, nodose, with deep sagittal stricture and small circular pores; two pairs of larger pores on each side of the stricture. Basal plate with four larger central and eight smaller peripheral pores. Apical horn conical, as long as the shell and twice as long as the two curved frontal horns. Three primary feet twice as long as the shell and as the three secondary feet, which are more highly inserted. All six feet slender curved, divergent.

Dimensions.—Shell 0.07 long, 0.11 broad; horn and secondary feet 0.08 long, primary feet 0.15 long.

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

4. Liriospyris turrita, Haeckel.

Shell ovate, campanulate, smooth, with sharp sagittal stricture and irregular roundish pores; three to four pairs of larger pores on each side of the stricture. Basal plate with four large collar pores. Three horns short and stout, conical, fenestrated at the base. Six feet slender, conical, nearly vertical, of equal size, only one-third as long as the shell.

Dimensions.—Shell 0.08 long, 0.06 broad; horns 0.01 long, feet 0.03 long.

Habitat.—Fossil in Barbados.

5. Liriospyris amphithecta, n. sp. (Pl. 95, fig. 7).

Shell nut-shaped, tuberculate, with distinct sagittal stricture and irregular roundish pores. Basal plate with six larger and twelve smaller pores. Three horns conical, the apical as long as the shell and twice as long as the curved frontal horns. Two pectoral feet cylindrical, very large, curved, divergent, about three times as long as the shell and as the four other feet, which are conical.

Dimensions.—Shell 0.08 long, 0.12 broad; apical horn 0.08, frontal horns 0.05 long; length of the two pectoral feet 0.2, of the four others 0.06.

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

Genus 455. Cantharospyris,^[73] n. gen.

Definition.—Zygospyrida with six basal feet, without apical horn.

The genus Cantharospyris differs from the preceding two hexapodal genera in the absence of horns on the coryphal face, and has therefore the same relation to them that the hornless Tristylospyris bears to the one-horned Tripospyris and the three-horned Triceraspyris.

1. Cantharospyris carabus, n. sp.

Shell nut-shaped, with deep sagittal stricture and irregular roundish pores. Basal plate with six larger pores. Six feet of different sizes, cylindrical, curved; three primary feet (one caudal and two pectoral) about as long as the shell and twice as long as the three secondary feet.

Dimensions.—Shell 0.08 long, 0.12 broad; feet 0.05 to 0.09 long.

Habitat.—Tropical Atlantic, Station 338, depth 1990 fathoms; Central Pacific, Station 268, depth 2900 fathoms.

2. Cantharospyris ateuchus, Haeckel.

Shell nut-shaped, tuberculate, with slight sagittal stricture and unequal circular pores. Basal plate with six larger pores. The two pectoral feet very large and stout, four to six times as long as the shell, widely divergent, curved. The four other feet much smaller and thinner, about as long as the shell.

Dimensions.—Shell 0.06 long, 0.08 broad; length of the two larger feet 0.2 to 0.3, of the four smaller 0.05 to 0.07.

Habitat.—Fossil in Barbados.

3. Cantharospyris radicata, Haeckel.

Shell nut-shaped, smooth, with slight sagittal stricture and irregular roundish pores; two larger pores on each side of the ring. Basal plate with six pores (?). Six feet of equal size and similar form, conical, divergent, slightly curved, shorter than half the ring.

Dimensions.—Shell 0.05 long, 0.08 broad; feet 0.02 long.

Habitat.—Fossil in Barbados and Sicily.

4. Cantharospyris platybursa, n. sp. (Pl. 53, fig. 7).

Shell smooth, nearly discoidal circular, markedly compressed in the sagittal direction, with slight basal stricture. Pores very numerous, irregular polygonal, with thin bars. Basal plate with four very large pores. Six feet short, conical, nearly horizontally expanded. Two sagittal feet (caudal and sternal) larger, about half as long as the shell (shortened in the figure). The two sternal feet larger than the two small or rudimentary tergal feet.

Dimensions.—Shell 0.15 long, 0.13 broad; feet 0.02 to 0.06 long.

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

Subfamily 5. Pentaspyrida, Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida pentapoda, with five descending basal feet, one odd caudal foot, and two pairs of lateral feet (two anterior or pectoral, and two posterior or tergal feet).

Genus 456. Clathrospyris,^[74] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with five basal feet and one apical horn.

The genus Clathrospyris and the two following closely allied genera represent together the small subfamily of Pentaspyrida, differing from the other Zygospyrida in the possession of five descending feet on the basal face. Three of these are the primary cortinar feet (of Cortiniscus, Plagoniscus, Tripospyris, &c.), whilst the two others are secondary tergal feet. The Pentaspyrida may therefore be probably derived from the Hexaspyrida by loss of the odd anterior or sternal foot.

1. Clathrospyris camelopardalis, n. sp.

Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish. Basal plate with six pores (?). Two pectoral feet very large, twice as long as the shell, cylindrical, curved. Two tergal feet half as long and thick as the pectoral. Caudal foot and apical horn straight, conical, half as long as the shell.

Dimensions.—Shell 0.07 long, 0.09 broad; horn and odd caudal foot 0.04 long; pectoral feet 0.16, tergal 0.08 long.

Habitat.—South Pacific, Station 297, depth 1775 fathoms.

2. Clathrospyris pyramidalis, n. sp. (Pl. 95, fig. 9).

Shell four-sided pyramidal, truncate, thorny, with a slight sagittal stricture. Pores very large, polygonal roundish. Two pairs of large pores on each side of the ring (at the frontal and the occipital plate). Lateral pores more numerous. Basal plate with four large pores. The four edges of the pyramid are prolonged into four short pyramidal divergent lateral feet (one-third as long as the shell). Caudal foot short. Horn at the apex of the truncate pyramid with two lateral teeth.

Dimensions.—Shell 0.06 long, 0.08 broad; horn and feet 0.02 long.

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

3. Clathrospyris fusiformis, n. sp.

Shell nearly cubical, smooth, with slight sagittal stricture. Pores roundish; three pairs of larger pores on each side of the ring. Basal plate with six large pores. Five feet of equal length, slender, spindle-shaped, about as long as the shell, divergent. Apical horn conical, and half as long as the feet.

Dimensions.—Shell 0.08 long, 0.09 broad; horn 0.05 long, feet 0.1 long.

Habitat.—Fossil in Barbados.

Genus 457. Aegospyris,^[75] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with five basal feet and three coryphal horns.

The genus Aegospyris differs from the preceding Clathrospyris, its ancestral form, in the possession of three horns on the coryphal face (one odd apical, and two paired frontal horns on each side), and therefore bears to the latter the same relation that Triceraspyris does to Tripospyris, and Liriospyris to Hexaspyris.

1. Aegospyris aequispina, n. sp.

Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores subregular circular. Basal plate with four large collar pores. Three horns and five feet all of equal size and similar form, slender conical, slightly curved, widely divergent, about as long as the shell.

Dimensions.—Shell 0.08 long, 0.11 broad; horns and feet 0.08 long.

Habitat.—Central Pacific, Stations 265 to 274, depth 2350 to 2925 fathoms.

2. Aegospyris octospina, n. sp.

Shell nearly cubical, smooth, with slight sagittal stricture. Pores subregular circular; two pairs of larger pores on each side of the ring. Basal plate with four large pores. Two paired horns and four paired feet of equal size and similar form, S-shaped curved, twice as long as the shell. Odd horn and odd feet half as long, straight, conical.

Dimensions.—Shell 0.08 long, 0.09 broad; six paired spines 0.2 long, two odd spines 0.1 long.

Habitat.—South Atlantic, Station 323, depth 1900 fathoms.

3. Aegospyris longibarba, Haeckel.

Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores subregular circular. Basal plate with four larger central, and eight smaller peripheral pores. Apical horn and caudal foot short, straight, conical; two frontal horns longer, curved; four paired feet slender, curved, twice as long as the shell.

Dimensions.—Shell 0.06 long, 0.08 broad; paired horns 0.03 long, paired feet 0.1 long.

Habitat.—Fossil in Barbados.

4. Aegospyris aegoceras, n. sp. (Pl. 95, fig. 10).

Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish. Basal plate with three large pores. Apical horn and caudal foot short, straight, spindle-shaped; two frontal horns as long as the shell, strongly curved; four paired feet also curved, at the distal end forked, divergent; the tergal thinner and as long as the shell, the pectoral thicker and twice as long.

Dimensions.—Shell 0.07 long, 0.09 broad; pectoral feet 0.1 long.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Aegospyris caprina, n. sp. (Pl. 86, fig. 8).

Shell nut-shaped, papillate, with sharp sagittal stricture. Pores irregular roundish, two pairs of larger pores on each side of the ring. Basal plate with six large pores. Eight spines all straight, subvertical and nearly parallel, cylindro-conical. Two frontal horns and two tergal feet about as long as the shell; odd horn shorter; odd foot longer. Two pectoral feet twice as long as the shell, club-shaped, with a spinulate knob at the distal end.

Dimensions.—Shell 0.06 long, 0.09 broad; pectoral feet 0.11 long.

Habitat.—Central Pacific, Station 271, surface.

Genus 458. Pentaspyris,^[76] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with five basal feet, without apical horn.

The genus Pentaspyris differs from the two preceding genera in the absence of any coryphal horn, and represents therefore the pentapodal form among the hornless Zygospyrida.

1. Pentaspyris pentacantha, n. sp. (Pl. 95, fig. 11).

Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish, two pairs of larger pores on each side of the ring. Basal plate with four larger pores. All five feet cylindrical, S-shaped curved, strongly divergent, with few short branches, the two pectoral feet twice as long as the shell and the two tergal feet; odd caudal foot shorter.

Dimensions.—Shell 0.08 long, 0.13 broad; pectoral feet 0.2 long, tergal feet 0.1, caudal foot 0.06.

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

2. Pentaspyris isacantha, n. sp.

Shell subspherical, smooth, with slight sagittal stricture. Pores small, regular circular. Basal plate with six large pores (?). All five feet equal, cylindrical, C-shaped curved, slightly divergent, about as long as the shell.

Dimensions.—Shell 0.08 long, 0.09 broad; feet 0.07 long.

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

Subfamily 6. Therospyrida, Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida tetrapoda with two pairs of descending basal feet, one pair corresponding to the anterior or pectoral, the other pair to the posterior or tergal feet of the Hexaspyrida.

Genus 459. Zygospyris,^[77] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with two pairs of lateral feet and an apical horn.

The genus Zygospyris and the following three genera represent together the peculiar subfamily of Therospyrida. These always possess four basal feet, like the Tetraspyrida; but whilst in the latter group two feet are sagittal, and two lateral, in the Therospyrida there are no sagittal feet at all, but the four feet are opposed in two lateral pairs; the anterior pair corresponds to the pectoral, the posterior to the tergal feet of the Hexaspyrida and Pentaspyrida; from these latter the Therospyrida have been derived by loss of the sagittal feet.

1. Zygospyris quadrupes, n. sp.

Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish, on each side of the ring two pairs of larger pores. Apical horn conical, straight. Four feet equal, straight, divergent, conical, about as long as the shell and the horn.

Dimensions.—Shell 0.08 long, 0.11 broad; horn and feet 0.1 long.

Habitat.—South Atlantic, Station 335, depth 1425 fathoms.

2. Zygospyris equus, n. sp. (Pl. 83, fig. 16).

Shell subspherical, rough, with slight sagittal stricture. Pores small and numerous, subregular circular; no larger annular pores. Apical horn cylindrical, half as long as the shell. Two pectoral feet somewhat smaller than the two tergal feet, about as long as the shell, slightly divergent, cylindrical. The distal ends of the feet and of the horn form an ovate, dimpled and spinulate cone.

Dimensions.—Shell 0.06 long, 0.09 broad; horn 0.04 long, feet 0.06 long.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

Genus 460. Elaphospyris,^[78] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with two pairs of lateral feet and three coryphal horns.

The genus Elaphospyris differs from the preceding Zygospyris, its ancestral form, in the possession of three coryphal horns (one odd apical and two paired frontal horns), and therefore bears to it the same relation that Triceraspyris does to Tripospyris among the Tripospyrida.

Subgenus 1. Giraffospyris, Haeckel, 1881, Prodromus, p. 442.

Definition.—Feet simple, not branched nor forked.

1. Elaphospyris heptaceros, Haeckel.

Shell nut-shaped, tuberculate, with slight sagittal stricture and subregular circular pores. Basal plate with four large pores. Apical horn small, conical, shorter than the two curved lateral horns, which are as long as the shell. Caudal and sternal feet small, conical, straight. Two pectoral feet slender, divergent, S-shaped, about as long as the shell.

Dimensions.—Shell 0.05 long, 0.07 broad; horns and feet 0.02 to 0.08 long.

Habitat.—Fossil in Barbados.

2. Elaphospyris capricornis, n. sp.

Shell nut-shaped, spiny, with slight sagittal stricture and numerous small circular pores. Basal plate with four large pores. Three horns slender, simple, about as long as the shell, the middle one straight, the two lateral curved. Four feet of nearly equal size, slender, curved, divergent, simple, twice as long as the shell and the horns.

Dimensions.—Shell 0.07 long, 0.09 broad; horns 0.08 long, feet 0.15 long.

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

Subgenus 2. Corythospyris, Haeckel, 1881, Prodromus, p. 443.

Definition.—Feet branched or forked.

3. Elaphospyris damaecornis, n. sp. (Pl. 84, fig. 10).

Shell flat and broad, nearly triangular, with slight sagittal stricture and irregular roundish pores; two very large pores on the frontal and on the occipital face, opposite on both edges of the broad sagittal ring. Basal plate with four large central and several smaller lateral pores. Three horns about half as long as the shell, with two to six irregular branches. Four feet of equal size, about as long as the shell, divergent, forked, with four to six irregular terminal branches. (The shell in fig. 10 is seen from the apical side.)

Dimensions.—Shell 0.09 long, 0.13 broad; horns 0.05 long, feet 0.1 long.

Habitat.—Indian Ocean, Cocos Islands, Rabbe, surface.

4. Elaphospyris cervicornis, n. sp. (Pl. 86, fig. 13).

Shell polyhedral, spiny, with deep sagittal stricture and a small number of large roundish pores; two pairs of large pores on each side of the ring. Basal plate with four pores. Three large horns as long as the shell arise from the apex between smaller conical spines; the middle odd horn simple, the two lateral each with a pair of branches. Two pectoral feet very large, divergent, with broad and irregular distal ramification, twice as long as the shell and as the two tergal feet, which are less branched. (Fig. 13 exhibits the shell from the dorsal side.)

Dimensions.—Shell 0.09 long, 0.11 broad; horns and smaller feet 0.07 to 0.09 long; pectoral feet 0.16 long.

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

5. Elaphospyris alcicornis, n. sp. (Pl. 86, fig. 12).

Shell nut-shaped, spiny, with sharp sagittal stricture and large roundish pentagonally framed pores; three pairs of larger pores on each side of the ring. Basal plate with four larger and four alternate smaller pores. There arise from the apex, between smaller spines, three large, divergent, pyramidal horns, which are nearly as long as the shell, and connected by an arched frontal bridge. Two pectoral feet very large, divergent, prismatic, longer than the shell, and at the distal end with a bunch of thick spines. Two tergal feet half as long and thick, simple (in the figure hidden behind the large pectoral feet).

Dimensions.—Shell 0.09 long, 0.11 broad; horns and smaller feet 0.06 long, pectoral feet 0.12 long.

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

Genus 461. Taurospyris,^[79] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with two pairs of lateral feet and one pair of lateral horns.

The genus Taurospyris bears only two frontal horns in the coryphal face of the shell, and may therefore be derived from the preceding closely allied Elaphospyris by reduction and loss of the middle or apical horn.

1. Taurospyris cervina, n. sp. (Pl. 95, fig. 12).

Shell nut-shaped, thorny, with deep sagittal stricture and irregular roundish pores; three pairs of larger pores on each side of the ring. Basal plate with four large pores. Two horns cylindrical, curved, widely divergent, about as long as the shell, branched. Four feet of nearly equal length, also cylindrical and curved, divergent, somewhat longer than the shell, in the distal half branched like a deer's antler.

Dimensions.—Shell 0.07 long, 0.11 broad; horns 0.03 long, feet 0.06 long.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms; also fossil in Barbados.

2. Taurospyris bovina, n. sp.

Shell subspherical, smooth, with slight sagittal stricture and small circular pores. Basal plate with six larger pores. Two horns conical, curved, divergent, about as long as the shell. Two pectoral feet very large, twice as long as the shell and as the two thinner tergal feet; all four feet curved, cylindrical, divergent, pointed at the distal end.

Dimensions.—Shell 0.08 long, 0.09 broad; horns and posterior feet 0.1, anterior feet 0.2 long.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

Genus 462. Therospyris,^[80] Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida with two pairs of lateral feet, without apical horn.

The genus Therospyris has two pairs of lateral feet corresponding to those of the preceding three genera, but differs from them in the complete absence of horns on the coryphal face of the shell.

1. Therospyris canis, n. sp.

Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular, roundish. Basal plate with four longer pores. Surface covered with roundish tubercles. Four feet equal, divergent, about as long as the shell, thickened at the distal end, club-shaped, not forked.

Dimensions.—Shell 0.07 long, 0.11 broad; feet 0.09 long.

Habitat.—Fossil in Barbados.

2. Therospyris felis, n. sp. (Pl. 89, fig. 6).

Shell nut-shaped, mammillate, with sharp sagittal stricture. Pores large, irregularly roundish or polygonal, of somewhat different size. Basal plate with four large pores. Surface covered with hemispherical pointed mammillæ. Four feet equal, divergent, half as long as the shell, at the distal end forked, with few small branches.

Dimensions.—Shell 0.1 long, 0.15 broad; feet 0.05 long.

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

3. Therospyris leo, n. sp. (Pl. 89, fig. 5).

Shell nearly cubical, papillate, with slight sagittal stricture. Pores irregular, roundish; on each side of the ring three pairs of larger pores (the undermost the largest). Basal plate with two large pores. Surface covered with conical papillæ. Four feet equal, divergent, about as long as the shell, with an external spur in the middle, and irregularly branched spines at the distal end.

Dimensions.—Shell 0.08 long, 0.12 broad; feet 0.09 long.

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

Subfamily 7. Polyspyrida, Haeckel, 1881, Prodromus, p. 442.

Definition.—Zygospyrida polypoda, with numerous descending basal feet (at least seven to nine, usually twelve to sixteen or more).

Genus 463. Petalospyris,^[81] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

Definition.—Zygospyrida with numerous (seven to twelve or more) basal feet and one apical horn.

The genus Petalospyris and the following three genera form together the peculiar subfamily of Polyspyrida, differing from the other Zygospyrida in the multiplication of the radial feet, which descend from the basal face of the shell; they may therefore be also called "Zygospyrida multiradiata," and bear the closest relationship to the Archiphænida (or the "Monocyrtida multiradiata"). They differ, however, from the latter in the presence of the distinct sagittal stricture, characteristic of all Spyroidea. The number of the basal feet, which form a coronet around the margin of the basal plate, is commonly between twelve and sixteen, but often more. Their form is usually flat, lamellar, but often also more or less cylindrical or conical.

Subgenus 1. Petalospyrantha, Haeckel.

Definition.—Basal plate with two large collar pores only, separated by the base of the primary ring.

1. Petalospyris foveolata, Ehrenberg.

Shell campanulate, smooth, with distinct sagittal stricture and subregular circular pores. Basal plate with two large collar pores only. Apical horn and the eight feet slender, conical, slightly curved, about as long as the shell; feet somewhat divergent (often seven or nine instead of eight).

Dimensions.—Shell diameter 0.04 to 0.05; length of the horn and the feet 0.04 to 0.05.

Habitat.—Fossil in Barbados.

2. Petalospyris floscula, n. sp.

Shell nut-shaped, tuberculate, with deep sagittal stricture and subregular circular pores. Basal plate with two large triangular pores only. Apical horn slender, conical, twice as long as the shell. Twelve to sixteen feet flattened, leaf-shaped, broad, slightly divergent, as long as the shell, with truncate distal end.

Dimensions.—Shell 0.06 long, 0.09 broad; horn 0.12 long, feet 0.05 to 0.07 long.

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

Subgenus 2. Petalospyrella, Haeckel.

Definition.—Basal plate with three large collar pores (two paired posterior cardinal, and an odd anterior sternal pore).

3. Petalospyris triomma, n. sp. (Pl. 87, fig. 14).

Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular roundish pores. Basal plate with three large pores and three alternate smaller. Apical horn stout, conical, half as long as the shell. Twelve to fifteen feet, divergent, curved, pointed, as long as the horn.

Dimensions.—Shell 0.06 long, 0.08 broad; horn and feet 0.03 long.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

4. Petalospyris platyacantha, Ehrenberg.

Shell campanulate, smooth, with slight sagittal stricture and small irregular roundish pores. Basal plate with three large pores (?). Apical horn very strong, three-sided pyramidal, twice as long as the shell (its edge is described by Ehrenberg as a "canaliculus.") Feet ten to twelve, flat, triangular, vertical, about as long as the shell.

Dimensions.—Shell 0.04 long, 0.05 broad; 0.07 long, feet 0.03 long.

Habitat.—Fossil in Barbados.

5. Petalospyris corona, Stöhr.

Shell nut-shaped, smooth, with slight sagittal stricture and very numerous small circular pores; on each side of the stricture three larger annular pores (the undermost the largest). Basal plate with three large pores only. Apical horn very small, conical. Feet twelve to eighteen, short conical, nearly vertical, shorter than the half shell (in my specimen from Caltanisetta much stouter than in that of Stöhr).

Dimensions.—Shell 0.07 long, 0.09 broad; horn and feet 0.01 to 0.03 long.

Habitat.—Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta).

Subgenus 3. Petalospyrissa, Haeckel.

Definition.—Basal plate with four collar pores (two larger posterior cardinal and two smaller anterior jugular pores).

6. Petalospyris octopus, n. sp. (Pl. 87, fig. 11).

Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular, roundish pores. Basal plate with four larger pores. Horn slender, conical, half as long as the shell. Feet eight, very slender, about three times as long as the shell, subvertical, with outer convex edge and convergent ends.

Dimensions.—Shell 0.06 long, 0.09 broad; horn 0.03 long, feet 0.2 long.

Habitat.—Tropical Atlantic, Station 342, depth 1445 fathoms.

7. Petalospyris eupetala, Ehrenberg.