Subgenus 1. Acrocorona, Haeckel, 1881, Prodromus, p. 430.

Definition.—Feet simple, not branched nor forked.

1. Calpophæna tetrarrhabda, n. sp.

Shell subspherical, tuberculate, with subregular circular pores. Apical horn conical, about as long as the shell. Basal plate with a regular cross of four equal cortinar pores, separated by four bars; these are crossed in the sagittal and frontal diameter, and prolonged into four equal conical divergent feet, about as long as the shell.

Dimensions.—Shell 0.1 diameter, horn and feet 0.1 to 0.12 long.

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

2. Calpophæna hexarrhabda, n. sp. (Pl. 53, figs. 17, 18).

Shell subspherical, rough, with irregular roundish pores. Apical horn conical, shorter than the shell. Basal plate (fig. 18) with three pairs of triangular pores, two larger (cardinal) pores in the middle, two smaller (cervical) at the dorsal, and two intermediate (jugular) at the ventral side. The bars between them are prolonged into six equal cylindrical divergent feet, nearly as long as the shell, provided with a spiny knob at the end.

Dimensions.—Shell 0.09 long, 0.08 broad; horn and feet 0.06 to 0.08 long.

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

3. Calpophæna ennearrhabda, n. sp.

Shell subspherical, spiny, with irregular, roundish pores. Apical horn cylindrical, longer than the shell. Basal plate with nine collar pores, three larger central alternating with three pairs of smaller peripheral (like Pl. 87, fig. 2). Corona with nine slender cylindrical, slightly curved, divergent feet, somewhat longer than the shell.

Dimensions.—Shell 0.11 long, 0.1 broad; horn and feet 0.12 to 0.15 long.

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

4. Calpophæna enneaphylla, n. sp.

Shell ovate, smooth, with regular circular pores. Apical horn pyramidal, half as long as the shell. (Basal plate with four cortinar pores?) Corona with nine broad, lamellar, truncate, vertical feet, about as long as the horn.

Dimensions.—Shell 0.12 long, 0.09 broad; horn and feet 0.06 long.

Habitat.—Central Pacific, Station 271, surface.

5. Calpophæna petalospyris, n. sp.

Shell campanulate, tuberculate, with irregular, roundish pores. Apical horn conical, shorter than the shell. (Basal plate with nine pores?) Corona with twelve to twenty broad, lamellar, truncate, vertical feet, of different sizes, somewhat irregular.

Dimensions.—Shell 0.08 long, 0.09 broad; horn and feet 0.07 to 0.12 long.

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

Subgenus 2. Cladocorona, Haeckel, 1881, Prodromus, p. 430.

Definition.—Feet branched or forked.

6. Calpophæna tetracorethra, n. sp.

Shell subspherical, smooth, with irregular, roundish pores. Basal plate with four larger pores. Apical horn and the four divergent basal feet of equal size and similar form, three to four times as long as the shell, slender, bristle-shaped, curved, in the distal half irregularly branched. (Very similar to the remarkable Tetraspyris tetracorethra, Pl. 53, figs. 19, 20, but with shorter appendages and with simple spherical shell, which exhibits no trace of sagittal ring and constriction.)

Dimensions.—Shell 0.12 diameter, horn and feet 0.3 to 0.5 long.

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

7. Calpophæna hexacorethra, n. sp.

Shell subspherical, smooth, similar to the preceding species. Basal plate with six pores. Apical horn and the six divergent feet twice to three times as long as the shell, bristle-shaped, irregularly curved and branched. (Similar to Hexaspyris hexacorethra, Pl. 95, fig. 8, but without sagittal ring and constriction.)

Dimensions.—Shell 0.11 long, 0.13 broad; horn and feet 0.2 to 0.3 long.

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

Genus 525. Archiphæna,^[142] Haeckel, 1881, Prodromus, p. 429.

Definition.—Archiphænida (vel Monocyrtida multiradiata clausa), with simple internal cavity of the shell, without apical horn and axial columella.

The genus Archiphæna has the same simple cavity of the shell as the preceding Calpophæna, but differs from it in the loss of the apical horn. It bears therefore to the latter the same relation that Gorgospyris does to Petalospyris. The two former genera may be derived from the two latter by loss of the sagittal ring and constriction.

Subgenus 1. Coronophæna, Haeckel, 1881, Prodromus, p. 429.

Definition.—Feet simple, not branched nor forked.

1. Archiphæna gorgospyris, n. sp. (Pl. 98, figs. 10, 10a).

Shell hemispherical, smooth, with small subregular, circular pores. Collar septum with four large pores (fig. 10a). Twelve to fifteen feet, divergent, lamellar, truncate, about as long as the shell. (Similar to certain forms of Gorgospyris, Pl. 87, figs. 1 to 3, but with simple shell cavity, without sagittal ring and constriction, and without a columella.)

Dimensions.—Shell 0.08 long, 0.04 broad; feet 0.03 to 0.04 long.

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

2. Archiphæna corona, n. sp.

Shell crown-shaped, somewhat broader than long, at the base flattened, papillate, with irregular roundish pores. Twenty to twenty-five feet, broad, lamellar, truncate, nearly vertical, about twice as long as the shell.

Dimensions.—Shell 0.1 long, 0.12 broad; feet 0.2 to 0.22 long.

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

Subgenus 2. Stephanophæna, Haeckel, 1881, Prodromus, p. 429.

Definition.—Feet branched or forked.

3. Archiphæna stephanoma, n. sp.

Shell campanulate, somewhat longer than broad, with subregular, circular pores. Margin of the flattened base with a corona of about twenty unequal feet, which are partly simple, partly irregularly branched, and about as long as the shell.

Dimensions.—Shell 0.11 long, 0.03 broad; feet 0.08 to 0.12 long.

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

Family LXI. Cyrtocalpida, n. fam.

Definition.—Monocyrtida eradiata. (Cyrtoidea with a simple, not jointed shell, representing a simple cephalis without radial apophyses.)

The family Cyrtocalpida, composed of the Archicorida and Archicapsida of my Prodromus, comprises those Cyrtoidea in which the lattice-shell is quite simple, without transverse constriction, and without radial apophyses. The two subfamilies differ in the shape of the basal mouth, which in the Archicorida is a simple wide opening, but in the Archicapsida is closed by a lattice-plate.

Only a few species of this family were formerly known. Ehrenberg, in 1838, founded upon these the genus Cornutella, one of the three oldest genera of Polycystina (Cornutella, Lithocampe, Haliomma). In 1862 I described some living forms, with a central capsule, as Cyrtocalpis. The Challenger collection contains a large number of new genera and species.

Probably the family Cyrtocalpida is an artificial group, comprising two or more different subfamilies of very different origin. The Cornutellida (Cornutella, Cornutanna) have probably been derived from the Sethocorida by loss of the cephalis, so that their conical shell represents a thorax alone. The Mitrocalpida on the other hand (genera 528-531) may be originally simple ovate shells (like Gromia and Lecythium), arising independently from the Nassellida. The Archicapsida (Halicapsa, Archicapsa) are probably derived from the Zygospyrida (Dictyospyris, Circospyris) by loss of the sagittal ring and constriction. This is nearly certain, when the three or four typical cortinar pores appear in their basal plate. Some forms of Halicapsa may be easily confounded with some forms of Prunoidea (Lithapium).

Those Cyrtocalpida, which possess a central capsule with three or four lobes, are probably derived from Tripocyrtida by loss of the three feet, or from Sethocyrtida by loss of the cephalis, since the lobes indicate the original presence of cortinar pores and of a cephalis. Those Cyrtocalpida, however, in which a simple ovate shell encloses a simple central capsule without lobes, may be original "Monocyrtida eradiata," without relation to any radial ancestral forms.

Synopsis of the Genera of Cyrtocalpida.

Subfamily 1. Archicorida, Haeckel, 1881, Prodromus, p. 427.

Definition.—Cyrtocalpida, with the basal mouth of the shell open (vel Monocyrtida eradiata aperta).

Genus 526. Cornutella,^[143] Ehrenberg, 1838, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 128.

Definition.—Archicorida with conical shell, gradually dilated towards the wide open mouth. Apex armed with a horn.

The genus Cornutella is one of the three oldest genera of Polycystina, described by Ehrenberg, in 1838 (Cornutella, Lithocampe, and Haliomma). He afterwards enumerated, in 1872 and 1875, a large number of fossil and living species, the majority of which, however, belong to other genera of Monocyrtida and Dicyrtida (at least six or seven different genera). We retain here as the true type of the genus the oldest known species:—Cornutella clathrata, and the nearly allied forms Cornutella stylophæna, Cornutella mitra, Cornutella circularis, &c. The simple conical shell exhibits no distinct trace of an original cephalis, excepting the apical horn; it may have originated either independently, or been derived from Sethoconus, by loss of the cephalis.

Subgenus 1. Cornutellium, Haeckel.

Definition.—Axis of the conical shell straight. Pores polygonal, or roundish with polygonal frames.

1. Cornutella hexagona, n. sp. (Pl. 54, fig. 9).

Shell slender, conical, with straight outlines. Pores subregular, hexagonal, gradually increasing in size towards the mouth; in about ten to twelve longitudinal series, in the upper part very small. Horn slenderly conical, nearly bristle-shaped, long.

Dimensions.—Shell 0.1 to 0.15 long, 0.04 to 0.06 broad.

Habitat.—Central Pacific, Stations 265 to 274, surface, and at different depths.

2. Cornutella sethoconus, n. sp. (Pl. 54, fig. 10).

Shell slender, conical, with undulate outlines. Pores subregular, hexagonal, gradually increasing in size towards the mouth, in about fifteen to eighteen longitudinal series, in the upper part circular. Horn small, conical, short. The network is not so delicate as in the preceding similar species.

Dimensions.—Shell 0.12 to 0.16 long, 0.06 to 0.08 broad.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

3. Cornutella distenta, Ehrenberg.

Shell slender, conical, with straight outlines. Pores small, circular, regularly disposed in six to eight alternating longitudinal rows, each pore surrounded by a large rhombic frame. The connected frames form together a regular rhombic framework with obliquely crossed crests. Horn conical, stout, large.

Dimensions.—Shell 0.1 to 0.15 long, 0.04 to 0.06 broad.

Habitat.—North Pacific, Californian Sea, depth 2600 fathoms, Ehrenberg.

4. Cornutella stiligera, Ehrenberg.

Shell slender, conical, with straight outlines. Pores subregular, rhombic or nearly square, disposed in oblique series, separated by parallel obliquely ascending rings, which are crossed by interrupted parallel bars. Horn slenderly conical or bristle-shaped, thin and long.

Dimensions.—Shell 0.08 to 0.12 long, 0.03 to 0.04 broad.

Habitat.—Fossil in Barbados.

Subgenus 2. Cornutissa, Haeckel, 1881, Prodromus, p. 427.

Definition.—Axis of the conical shell straight. Pores circular or roundish, without polygonal frames.

5. Cornutella circularis, Ehrenberg.

Shell wide, conical or funnel-shaped, with straight outlines. Pores very large, circular, ten to twenty times as broad as the bars, in about nine to twelve longitudinal alternating rows, increasing gradually towards the mouth. Horn very large, cylindrical.

Dimensions.—Shell 0.1 to 0.15 long, 0.08 to 0.12 broad.

Habitat.—Fossil in Barbados.

6. Cornutella mitra, Ehrenberg.

Shell wide, conical, campanulate, with convex outlines. Pores subregular, circular, nearly equal in size, not regularly disposed in rows. Horn conical, stout.

Dimensions.—Shell 0.12 to 0.16 long, 0.08 to 0.12 broad.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.

7. Cornutella clathrata, Ehrenberg.

Shell wide, conical with slightly convex outlines. Pores regular, circular, gradually increasing in size towards the mouth, disposed in twelve to fifteen longitudinal alternating rows. Horn short and stout, conical. (Compare Cornutella curvata.)

Dimensions.—Shell 0.15 to 0.2 long, 0.06 to 0.09 broad.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific; also fossil in tertiary rocks of Barbados, Nikobar and Sicily.

8. Cornutella stylophæna, Ehrenberg.

Shell slender, conical, with undulate outlines. Pores subregular, circular, gradually increasing in size, disposed in six to nine quincuncial alternating longitudinal rows. Horn very long, cylindro-conical, sometimes about as long as the shell.

Dimensions.—Shell 0.1 to 0.13 long, 0.04 to 0.06 broad.

Habitat.—North Pacific, Californian Sea, depth 2600 fathoms.

9. Cornutella granulata, Ehrenberg.

Shell slender, conical, nearly cylindrical, with straight outlines, rounded at the apex. Pores very small and numerous, punctiform, disposed into very numerous parallel transverse rows. Horn small, conical (may be perhaps the shell of a Tintinnoid Infusorium?).

Dimensions.—Shell 0.08 long, 0.02 broad.

Habitat.—North Pacific, Californian Sea, depth 2600 fathoms.

10. Cornutella annulata, Ehrenberg.

Shell slender, conical, nearly cylindrical, with straight outlines, rounded at the apex. Pores small and numerous, regular circular, of equal size, regularly disposed in ten to fifteen parallel transverse series. Horn bristle-shaped. (Compare Artostrobus annulatus, Cornutella annulata, Bailey.)

Dimensions.—Shell 0.1 to 0.13 long, 0.03 to 0.04 broad.

Habitat.—Cosmopolitan, Atlantic, Pacific, surface.

Subgenus 3. Cornutosa, Haeckel, 1881, Prodromus, p. 427.

Definition.—Axis of the conical shell curved. Pores circular or roundish.

11. Cornutella curvata, Haeckel.

Shell slender, conical, with curved axis; the curve lies in one plane and is not spirally convoluted. Pores subregular, circular, of nearly equal size, quincuncially disposed. Horn short, conical.

Dimensions.—Shell 0.1 to 0.15 long, 0.04 to 0.06 broad.

Habitat.—Fossil in tertiary rocks of Sicily (Caltanisetta).

12. Cornutella spiralis, n. sp.

Shell slender, conical, nearly cylindrical, very long, spirally contorted; its axis is an ascending spiral line with two or three windings, widely distant. Pores irregular, square, small and numerous.

Dimensions.—Shell 0.2 to 0.25 long, 0.05 to 0.08 broad.

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

Genus 527. Cornutanna,^[144] Haeckel, 1881, Prodromus, p. 427.

Definition.—Archicorida with conical shell, gradually dilated towards the wide open mouth. Apex without horn.

The genus Cornutanna has the same simple conical shell as the preceding Cornutella, but differs from it in the total absence of an apical horn. It bears therefore to the latter the same relation that Cyrtocalpis does to Archicorys. It may be derived from Sethoconus by complete reduction of the cephalis and its horn.

1. Cornutanna orthoconus, n. sp.

Shell slender, conical, with straight axis and straight outlines. Pores subregular, circular, quincuncially disposed in nine to twelve alternating longitudinal series, gradually increasing in size towards the mouth.

Dimensions.—Shell 0.1 to 0.12 long, 0.03 to 0.04 broad.

Habitat.—Central Pacific, Stations 270 to 274, surface.

2. Cornutanna cyrtoconus, n. sp.

Shell slender, conical, with curved axis; the curve lies in one plane as in the similar Cornutella curvata; the pores are smaller and more numerous than in this latter species, and the rounded apex bears no horn.

Dimensions.—Shell 0.12 to 0.16 long, 0.05 to 0.07 broad.

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

3. Cornutanna loxoconus, n. sp.

Shell wide, conical, with irregularly curved axis; the parts of the curve do not lie in one plane. Pores very small and numerous, of nearly equal size.

Dimensions.—Shell 0.2 long, 0.12 broad.

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

Genus 528. Archicorys,^[145] Haeckel, 1881, Prodromus, p. 427.

Definition.—Archicorida with simple urceolate or ovate shell, constricted towards the mouth. Apex armed with a horn.

The genus Archicorys and the following closely allied Cyrtocalpis differ from the two preceding genera in the ovate or urceolate form of the shell, which is more or less constricted towards the terminal mouth. The upper pole in Archicorys bears an apical horn, which is absent in Cyrtocalpis. The origin of these two genera may be the same, probably arising directly from Nassellida, and independently of the triradiate Cyrtoidea or bilocular Spyroidea. (Compare p. 1179.)

1. Archicorys galea, n. sp.

Shell smooth urceolate. Pores large, in the middle part hexagonal, towards both ends smaller and polygonal. Apical horn stout, three-sided pyramidal, half as long as the shell. Mouth with a short tubular peristome, about one-third as broad as the shell.

Dimensions.—Shell (without horn) 0.15 long, 0.12 broad; horn 0.07 long, mouth 0.05 broad.

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

2. Archicorys ampulla, n. sp.

Shell smooth, thin-walled, bottle-shaped, in the upper half conical, in the lower half inflate, subspherical. Pores subregular, circular, of the same breadth as the bars. Horn conical, stout, /about one-third as long as the shell. Mouth truncate, without peristome, about half as broad as the shell.

Dimensions.—Shell 0.15 long, 0.1 broad; horn 0.05, mouth 0.05.

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

3. Archicorys microstoma, n. sp. (Pl. 51, fig. 12).

Shell rough, thick-walled, ovate. Pores large, subregular, circular, twice to four times as broad as the bars. Horn small, conical, not larger than one pore. Mouth very small, truncate, scarcely larger than one pore.

Dimensions.—Shell 0.1 long, 0.07 broad; horn 0.012, mouth 0.015.

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

4. Archicorys globosa, n. sp.

Shell nearly spherical, thorny, thick-walled. Pores very large, circular, separated by spinulate frames, smaller towards each pole. Horn conical, large, nearly as long as the radius of the shell; mouth truncate, simple, about one-third as broad as the shell.

Dimensions.—Shell diameter 0.13, horn 0.06, mouth 0.04.

Habitat.—Fossil in Barbados.

5. Archicorys ovata, n. sp. (Pl. 51, fig. 10).

Shell ovate, rough, thick-walled. Pores regular, circular, of equal size, very small and numerous, quincuncially disposed. Horn small, conical, sometimes (as in the figured specimen) rudimentary. When it becomes lost, the species may be called Cyrtocalpis ovata. Mouth truncate, small, simple, one-sixth as broad as the shell.

Dimensions.—Shell 0.2 long, 0.15 broad; horn 0.01 to 0.03 long, mouth 0.03 broad.

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

Genus 529. Cyrtocalpis,^[146] Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 835.

Definition.—Archicorida with simple urceolate or ovate shell, constricted towards the mouth. Apex without horn.

The genus Cyrtocalpis comprises a large number of common, very primitive Monocyrtida, which in the simple ovate or urceolate form of the shell resemble the well known Gromia among the Thalamophora. Its basal mouth is more or less constricted, as in the preceding genus Archicorys, from which it differs in the total absence of an apical horn. There is no trace of any triradial structure, excepting in some smaller species, in which the basal part of the central capsule is trilobate; these may be derived from the Dicyrtides Sethocorys or Dictyocephalus, by loss of the cephalis and the cortinar septum. But the larger species, which have a quite simple, ovate, central capsule (Pl. 51, fig. 13), have probably an independent origin, from Cystidium.

1. Cyrtocalpis urceolus, n. sp. (Pl. 51, fig. 13).

Shell smooth, urceolate, with very delicate and elegant network. Pores in the middle part large, regular, hexagonal, towards each pole smaller, irregular, roundish or polygonal. Mouth with broad, hyaline, annular peristome, about one-third as broad as the shell.

Dimensions.—Shell 0.16 long, 0.12 broad; mouth 0.05 broad.

Habitat.—Mediterranean (Portofino near Genoa), surface.

2. Cyrtocalpis reticulum, n. sp.

Shell smooth, urceolate, very similar to the preceding species, but differing from it in the densely reticulated framework of the shell, which is composed of very numerous and small, irregular, polygonal meshes of nearly equal size. Mouth without peristome, half as broad as the shell.

Dimensions.—Shell 0.18 long, 0.15 broad; mouth 0.07 broad.

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

3. Cyrtocalpis amphora, Haeckel.

Shell smooth, urceolate with regular, circular pores of equal size, of about the same breadth as the bars. Mouth with smooth peristome, about half as broad as the shell.

Dimensions.—Shell 0.12 long, 0.08 broad; mouth 0.04 broad.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific; surface, and at various depths.

4. Cyrtocalpis urna, Stöhr.

Shell smooth, urceolate, with subregular, circular pores of different sizes, gradually increasing towards the mouth, of about the same breadth as the bars. Mouth without peristome (?), about half as broad as the shell.

Dimensions.—Shell 0.09 long, 0.06 broad; mouth 0.035 broad.

Habitat.—Fossil in tertiary rocks of Sicily (Grotte).

5. Cyrtocalpis sethopora, n. sp. (Pl. 52, fig. 4).

Shell smooth, urceolate, very thin-walled, with large irregular roundish meshes, each of which is closed by a thin porous sieve-plate. Mouth two-thirds as broad as the shell, with a broad, emarginate, longitudinally striped peristome. (Perhaps the shell of a Tintinnoid Infusorium?)

Dimensions.—Shell 0.08 long, 0.05 broad; mouth 0.03 broad.

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

6. Cyrtocalpis compacta, n. sp. (Pl. 52, figs. 7, 8).

Shell smooth, ovate, very thick-walled, with small, subregular, circular pores of equal size, perpendicularly perforating the wall, about half as broad as the bars. Mouth small, only one-third as broad as the compact shell. (Perhaps a reduced Lithocampe or Lithomitra?)

Dimensions.—Shell 0.08 long, 0.04 broad; mouth 0.015 broad.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.

7. Cyrtocalpis lithomitra, n. sp. (Pl. 52, figs. 5, 6).

Shell smooth, slender, ovate, nearly cylindrical, with small subregular, circular pores, which are disposed in nine to twelve transverse rows, and obliquely ascending perforate the wall. Mouth wide, without peristome, about two-thirds as broad as the shell. (Compare Lithomitra, Pl. 79.)

Dimensions.—Shell 0.09 long, 0.045 broad; mouth 0.03 broad.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms; also fossil in Barbados.

8. Cyrtocalpis ovulum, n. sp.

Shell smooth, broad, ovate, with very numerous and small regular circular pores, quincuncially disposed, twice as broad as the bars. Mouth without peristome, about half as broad as the shell.

Dimensions.—Shell 0.09 long, 0.047 broad; mouth 0.04 broad.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.

9. Cyrtocalpis obliqua, Haeckel.

Shell smooth, irregularly ovate, more or less oblique, variable in size and form, sometimes nearly spherical, at other times subcylindrical. Pores subregular, circular, once or twice the breadth of the bars. Mouth simple without peristome, about half as broad as the shell.

Dimensions.—Shell 0.07 to 0.1 long, 0.05 to 0.08 broad; mouth 0.03 to 0.04 broad.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.