Chapter XI: Literature and History (14)

Proportion of the longer axis to the shorter = 2 : 1. Network of the thin wall regular or subregular. All pores circular, nearly of the same size, without hexagonal frame, three to four times as broad as the bars; eight to nine on the half equator. Surface covered with small thorns.

_Dimensions._--Longer axis of the ellipsoid 0.16 to 0.2, shorter axis 0.08 to 0.1; pores 0.1, bars 0.003.

_Habitat._--Fossil in the Tertiary rocks of Barbados (Ehrenberg, Haeckel).

4. _Cenellipsis circopora_, n. sp.

Proportion of the longer axis to the shorter = 5 : 3. Network of the thin wall delicate and regular. All pores circular, nearly of the same size, without hexagonal frame, twice as broad as the bars; fifteen to twenty on the half equator. Surface quite smooth.

_Dimensions._--Longer axis of the ellipsoid 0.15 to 0.2, shorter axis 0.09 to 0.12; pores 0.08, bars 0.4.

_Habitat._--North Pacific, Station 236, surface.

5. _Cenellipsis micropora_, n. sp.

Proportion of the longer axis to the shorter = 5 : 4. Network of the thick wall quite regular. All pores circular, without hexagonal frame, very small, scarcely half as broad as the bars; six to eight on the half equator. Surface quite smooth.

{292}_Dimensions._--Longer axis of the ellipsoid 0.1, shorter axis 0.08; pores 0.004, bars 0.01.

_Habitat._--South Pacific, Station 289, surface.

Subgenus 2. _Cenellipsula_, Haeckel.

_Definition._--Network of the shell irregular, with meshes of different size or form.

6. _Cenellipsis heteropora_, n. sp.

Proportion of the longer axis to the shorter = 3 : 2 or = 5 : 3. Network of the thin wall very irregular, with polygonal meshes of different size and form (for the most part pentagonal or hexagonal, but also many tetragonal or heptagonal). The largest pores four to six times as broad as the smallest; ten to twenty pores on the half equator; bars between them thin. Surface smooth or somewhat spiny.

_Dimensions._--Longer axis of the ellipsoid 0.18 to 0.22, shorter axis 0.1 to 0.12; pores 0.004 to 0.008, bars 0.001.

_Habitat._--Indian Ocean, near the Cocos Islands, surface, Rabbe.

7. _Cenellipsis maxima_, n. sp.

Proportion of the longer axis to the shorter = 3 : 2. Network of the thin wall very irregular, with polygonal meshes of very different size and form, twice to eight times as broad as the bars; fifty to sixty on the half equator. Surface smooth.

_Dimensions._--Longer axis of the ellipsoid 0.36, shorter axis 0.25; pores 0.004 to 0.015, bars 0.002.

_Habitat._--Equatorial Atlantic, Station 347, surface.

8. _Cenellipsis ovulum_, n. sp.

Proportion of the longer axis to the shorter = 3 : 2. Network of the thin wall very irregular, with roundish or longish pores of very different size and form. Pores flat, with even margins, thirty to forty on the half equator, twice to six times as broad as the bars. Surface smooth. (This species being observed alive, showed a transparent central capsule of ellipsoidal form, two-thirds as large as the shell.)

_Dimensions._--Longer axis of the ellipsoid 0.3, shorter axis 0.2; pores 0.04 to 0.012, bars 0.002.

_Habitat._--Indian Ocean, Ceylon, Haeckel; Pacific, central area, Station 266, surface.

9. _Cenellipsis infundibulum_, n. sp. (Pl. 39, fig. 2).

Proportion of the longer axis to the shorter = 3 : 2. Network of the thick wall irregular, with roundish pores of different size and form. Pores funnel-like, with prominent, irregular, spiny {293}crests between them, their outer aperture three to four times as broad as the inner; twelve to fifteen pores on the half equator. Surface prickly.

_Dimensions._--Longer axis of the ellipsoid 0.14, shorter axis 0.11; outer aperture of the pores 0.01 to 0.012, inner aperture 0.003 to 0.004.

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

10. _Cenellipsis oblonga_, n. sp.

Proportion of the longer axis to the shorter = 2 : 1. Network of the thick wall irregular, with roundish pores of different size and form. Pores with prominent conical edges, about as broad as the bars; twenty to twenty-five on the half equator. Sometimes each pore is prolonged into a short conical tubulus.

_Dimensions._--Longer axis of the ellipsoid 0.22, shorter axis 0.12; pores and bars 0.008 to 0.012.

_Habitat._--Pacific, central area, Station 265, depth 2900 fathoms.

Genus 123. _Axellipsis_,[162] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal shell, without radial spines or polar tubes, but with an inner transverse axial rod, which corresponds to the shorter axis of the ellipsoid.

The genus _Axellipsis_ differs from the simple _Cenellipsis_ in a very peculiar character, namely, the presence of an inner siliceous bar marking the minor axis of the ellipsoidal shell. If in some forms of _Druppula_ (e.g., Pl. 39, fig. 3) we remove the central medullary shell and prolong both beams (connecting it with the cortical shell) till they unite in the centre, we shall arrive at _Axellipsis_. Therefore _Axellipsis_ may be derived in the same way from _Druppula_ as _Axoprunum_ is from _Lithatractus_, by phyletic loss of the medullary shell.

1. _Axellipsis perforata_, n. sp.

Proportion of the major axis of the ellipsoid to the minor = 3 : 2. Pores of the shell regular, circular, twice as broad as the bars; ten to twelve on the half equator. Surface smooth.

_Dimensions._--Longer axis of the shell 0.12, shorter axis 0.08; pores 0.006, bars 0.003.

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

2. _Axellipsis lobata_, n. sp.

Proportion of the major axis to the minor = 5 : 4. Meshes of the shell irregular, roundish, lobed, with three to six indentations (each mesh formed by the confluence of three to six, commonly {294}four or five, smaller pores); eight to nine meshes on the half equator, these being twice to four times as broad as the bars.

_Dimensions._--Longer axis of the shell 0.1, shorter axis 0.08; pores 0.007 to 0.01, bars 0.003.

_Habitat._--Tropical zone of the Western Pacific, Station 225, surface.

Genus 124. _Ellipsidium_,[163] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal shell, with numerous radial spines on the surface, without polar spines or tubes.

The genus _Ellipsidium_ differs from _Cenellipsis_ solely in the development of numerous radial spines on the surface, and exhibits the same phylogenetic relation to it that _Heliosphæra_ bears to _Cenosphæra_.

1. _Ellipsidium pandanidium_, n. sp.

Proportion of the longer axis of the ellipsoid to the shorter = 5 : 4. Shell thick walled, with regular and hexagonal meshes, twice as broad as the bars; eighteen to twenty on the half equator. In each hexagon-corner (between three pores) arises a short, three-sided pyramidal spine, half as long as the equatorial radius, and as thick at the base as a single mesh.

_Dimensions._--Major axis of the ellipsoid 0.15, minor 0.12; pores 0.006, bars 0.003; length of the radial spines 0.03, basal breadth 0.006.

_Habitat._--Fossil in the Tertiary rocks of Barbados (Haeckel).

2. _Ellipsidium datura_, n. sp.

Proportion of the longer axis of the ellipsoid to the shorter = 4 : 3. Shell thick walled, with regular, circular meshes, twice as broad as the thick bars between them eight to ten meshes on the half equator. Outer surface of the shell thorny, covered with short, conical, radial spines, which are regularly distributed (one spine between every three meshes), and about as long as the diameter of the meshes. (The shell is similar to the outer shell of _Haliomma castanea_, Haeckel, Monogr. d. Radiol., Taf. xxiv. fig. 4.)

_Dimensions._--Major axis of the ellipsoid 0.12, minor axis 0.09; meshes 0.012, bars 0.006.

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

3. _Ellipsidium artocarpus_, n. sp.

Proportion of the longer axis to the shorter = 3 : 2. Shell thick walled, with regular, circular meshes, separated by deep furrows, which represent a regular, hexagonal framework; on the half equator twelve to fifteen meshes, scarcely broader than the broad bars between them. Outer {295}surface spiny; between every three meshes arises a strong radial spine, twice to three times as long as the diameter of the meshes; the base of the spine is like a three-sided pyramid.

_Dimensions._--Major axis of the ellipsoid 0.12, minor axis 0.08; meshes 0.006, bars 0.005.

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

4. _Ellipsidium opuntia_, n. sp.

Proportion of the longer axis to the shorter = 5 : 4. Shell thin walled, with irregular, roundish meshes of different size and form, about twice to three times as broad as the irregular, thin bars between them; ten to fifteen meshes on the half equator. Between the meshes arise numerous thin, bristle-like, radial spines, about as long as the shorter radius of the shell. The number of the meshes may be three to four times as great as the number of the spines.

_Dimensions._--Major axis of the ellipsoid 0.15, minor axis 0.12; pores 0.006 to 0.01, bars 0.003 to 0.004.

_Habitat._--Southern Pacific, Station 284, surface.

5. _Ellipsidium echinidium_, n. sp.

Proportion of the longer axis to the shorter = 4 : 3. Shell thick walled, with irregular, roundish pores of different size and form, about as large or somewhat smaller than the broad bars; twelve to sixteen pores on the half equator. On the surface, irregularly scattered, twenty to thirty strong, three-sided pyramidal, radial spines, one-fourth to one-half as long as the main axis.

_Dimensions._--Major axis of the ellipsoid 0.16, minor 0.12; pores and bars 0.002 to 0.008; length of the radial spines 0.04 to 0.08, basal breadth 0.01.

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

Genus 125. _Ellipsoxiphus_,[164] Dunikowski, 1882, Denkschr. d. k. Akad. d. Wiss. Wien, vol. xlv. p. 25.

_Definition._--#Ellipsida# with simple ellipsoidal shell, the main axis of which is prolonged at both poles into two strong opposite spines of equal size and similar form.

The genus _Ellipsoxiphus_ was established by Dunikowski (in 1882, _loc. cit._) for those simple amphistylous fenestrated shells, formerly united with _Xiphosphæra_, in which the mathematical form of the shell itself is not a true sphere, but an ellipsoid. It may therefore be derived from _Xiphosphæra_ by prolongation of the axis in which lie both polar spines; but it may also be derived from _Cenellipsis_ by the production of two equal spines at the poles of the main axis.

{296}Subgenus 1. _Ellipsoxiphetta_, Haeckel.

_Definition._--Network of the shell regular, with pores of equal size and similar form.

1. _Ellipsoxiphus elegans_, n. sp. (Pl. 14, fig. 7).

Proportion of the major axis of the ellipsoid to the minor = 5 : 4. Shell thick walled, with regular, circular meshes, separated by a regular, hexagonal elevated framework. From each hexagon-corner arises (between every three meshes) a short thin spine, about as long as the diameter of a mesh; twelve to fourteen meshes on the half equator, of the same breadth as the bars. Polar spines three-sided prismatic, cuspidate, about as long as the axis of the shell. (This elegant and not uncommon species is remarkable for its variations. By unequal development of both spines it passes over to _Ellipsostylus_.) In the figured variety (Pl. 14, fig. 7) the ends of the surface spines are connected by a very delicate network, so as to form an outer veil. This may further be separated as a peculiar genus _Ellipsoxiphium palliatum_.

_Dimensions._--Longer axis 0.08 to 0.13, shorter axis 0.06 to 0.11; pores and bars 0.008; length of the polar spines 0.06 to 0.12, basal breadth 0.01.

_Habitat._--Pacific, central area, Stations 270 to 274, from 2350 to 2925 fathoms.

2. _Ellipsoxiphus flosculus_, n. sp.

Proportion of the major axis to the minor = 6 : 5. Shell very thick walled, with regular, hexagonal meshes, eight to nine on the half equator, three to four times as broad as the bars. The inner contour of the meshes is circular, the outer six-lobed (similar to _Xiphostylus phasianus_, Pl. 13, fig. 9). Polar spines three-sided pyramidal, about as long as the major axis of the shell; their basal thickness equals one mesh.

_Dimensions._--Longer axis 0.12, shorter axis 0.1; pores 0.012 to 0.015, bars 0.004; length of the polar spines 0.12 to 0.15, basal breadth 0.015.

_Habitat._--Fossil in the Tertiary rocks of Barbados (Teuscher).

3. _Ellipsoxiphus fragilis_, n. sp.

Proportion of the major axis to the minor = 4 : 3. Shell thin walled, with regular, circular meshes, twice as broad as the bars; ten to twelve on the half equator. Surface smooth. Polar spines cylindrical, at the apex conical, half as long as the major axis.

_Dimensions._--Longer axis 0.16, shorter axis 0.12; pores 0.008, bars 0.004; length of the polar spines 0.09, basal breadth 0.008.

_Habitat._--South Atlantic, Station 325, surface.

Subgenus 2. _Ellipsoxiphilla_, Haeckel.

_Definition._--Network of the shell irregular, with pores of different size or form.

{297}4. _Ellipsoxiphus claviger_, n. sp. (Pl. 14, fig. 3).

_Xiphosphæra clavigera_, Haeckel, 1881, Prodromus et Atlas.

Proportion of the major axis to the minor = 5 : 4. Shell thick walled, with irregular network; meshes roundish or circular, double contoured, of unequal size, twice to four times as broad as the bars; eight to ten on the half equator. Polar spines club-shaped, with prominent edges, about as long as the minor axis; thicker in their middle part than at both ends (differs from _Xiphosphæra clavigera_ by the ellipsoidal form of the shell, and the double length of the spines).

_Dimensions._--Longer axis 0.15. shorter axis 0.12; pores 0.007 to 0.015, bars 0.004; length of the polar spines 0.12, thickness in the middle part 0.02.

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

5. _Ellipsoxiphus suessi_, Dunikowski.

_Ellipsoxiphus suessi_, Dunikowski, 1882, Denkschr. d. k. Akad. d. Wiss.
Wien, Bd. xlv. p. 26, Taf. v. fig. 50.

Proportion of the major axis to the minor = 7 : 5. Shell thick walled, with irregular, roundish meshes, six to eight on the half equator, twice to three times as broad as the bars. Polar spines nearly cylindrical, blunt, as long as the major axis.

_Dimensions._--Longer axis 0.14; shorter axis 0.1; pores 0.018 to 0.023, bars 0.01; length of the polar spines 0.12; thickness of them 0.035.

_Habitat._--Fossil in the Alpine Lias, Schafberg near Salzburg, Dunikowski.

6. _Ellipsoxiphus parvoforaminus_, Dunikowski.

_Ellipsoxiphus parvoforaminus_, Dunikowski, 1882, Denkschr. d. k. Akad.
d. Wiss. Wien, Bd. xlv. p. 26, Taf. v. fig. 51.

Proportion of the major axis to the minor = 7 : 6. Shell thick walled, with irregular, roundish or oval meshes, ten to twelve on the half equator, scarcely as broad as the bars. Polar spines conical, shorter than the minor axis.

_Dimensions._--Longer axis 0.14, shorter axis 0.12; pores 0.016 to 0.01, bars 0.01 to 0.02; length of the polar spines 0.1, basal thickness 0.045.

_Habitat._--Fossil in the Alpine Lias, Schafberg near Salzburg, Dunikowski.

7. _Ellipsoxiphus bipolaris_, n. sp. (Pl. 14, fig. 11).

_Xiphosphæra bipolaris_, 1881, Prodromus et Atlas.

Proportion of the major axis to the minor = 8 : 7. Shell thick walled, with irregular, roundish meshes, twice to three times as broad as the bars; sixteen to twenty on the half equator. Polar spines short and thick, three-sided pyramidal, scarcely half as long as the shorter radius of the shell; surrounding the base of every spine is a circle of eight to nine shorter spines.

_Dimensions._--Longer axis 0.08, shorter axis 0.07; pores 0.003 to 0.007, bars 0.002; length of the polar spines 0.02 to 0.03, basal thickness 0.02.

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

{298}8. _Ellipsoxiphus atractus_, n. sp. (Pl. 14, fig. 1).

Proportion of the major axis to the minor = 3 : 2. Shell spindle-shaped, very thick walled, with roundish, very irregular meshes, twice to five times as broad as the bars; eight to twelve on the half equator. The meshes are partly simple, oblong, partly lobed or composed of two to four (commonly three) confluent meshes. Surface smooth. Polar spines very short and thick, shorter than the minor radius of the shell, three-sided pyramidal, with prominent, somewhat contorted edges.

_Dimensions._--Longer axis 0.15, shorter axis 0.1; meshes 0.007 to 0.02, bars 0.004; length of the polar spines 0.04, basal thickness 0.03.

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

Genus 126. _Axoprunum_,[165] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal shell, the main axis of which is prolonged at both poles into two opposite spines of equal size and similar form. Within the cavity of the shell four radial rods arise from its inner surface, two in the main axis, two in the smallest axis, perpendicular to the former; their free inner ends are at the same distance from the centre.

The genus _Axoprunum_ possesses precisely the same shell as the foregoing _Ellipsoxiphus_, but differs from it in a very remarkable peculiarity. The two polar spines are centripetally prolonged into two internal beams, and perpendicular to these are two other, opposite, transverse beams, marking the minor axis of the ellipsoid. The free inner ends of all four radial rods bear little thickened knobs, and are at the same distance from the centre. It therefore appears as though a central, spherical, medullary shell had been lost, and this gives a strong support to the important hypothesis, that in many #Sphærellaria#, where the medullary shell is absent, it may have been lost by phylogenetic reduction or retrograde metamorphosis. In this case _Axoprunum_ (and _Ellipsoxiphus_) would arise from _Lithatractus_.

1. _Axoprunum stauraxonium_, n. sp. (Pl. 48, fig. 4).

Shell ellipsoidal, one and one-third times as long as broad, with smooth surface. Network regular, with circular meshes four times as broad as the bars. Two polar spines three-sided pyramidal, half as long as the shell, as thick at the base as a single mesh. Four inner radial beams (lying, two in the major and two in the minor axis of the ellipsoid) very thin, at the central free ends knob-like, thickened. The distance between two opposite beams equals one-third of the minor axis, and indicates probably the diameter of the lost spherical medullary shell. (Three perfect and complete specimens of the same size and shape were observed.)

{299}_Dimensions._--Major axis of the ellipsoid 0.14, minor axis 0.11; pores 0.012, bars 0.003; length of the polar spines 0.07, basal breadth 0.012. (Diameter of the lost medullary shell 0.03?)

_Habitat._--South Atlantic, Station 338, depth 1990 fathoms.

Genus 127. _Ellipsostylus_,[166] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal shell, the main axis of which is prolonged at both poles into two opposite spines of different size or form.

The genus _Ellipsostylus_ differs from _Ellipsoxiphus_ only in the unequal size or different form of the polar spines, which in the former are equal. This difference does not seem important at first, but in the further development it produces very singular and strange forms. Theoretically it is always important, because the fundamental haplopolar form of the monaxon body becomes diplopolar by this differentiation.

Subgenus 1. _Ellipsostyletta_, Haeckel.

_Definition._--Network of the shell regular, with pores of equal size and similar form.

1. _Ellipsostylus ornithoides_, n. sp.

Proportion of the major axis of the ellipsoid to the minor = 4 : 3. Shell thin walled, with regular, circular meshes and hexagonal framework between them, like that of _Xiphostylus favosus_ (Pl. 13, fig. 4). Circular pores about as broad as the bars; eight to nine on the half equator. Surface smooth. Polar spines three-sided pyramidal, as broad at the base as a single hexagon; the longer spine as long as the major axis, the shorter half as long.

_Dimensions._--Longer axis of the ellipsoidal shell 0.16, shorter axis 0.12; pores and bars 0.006; length of the longer polar spine 0.16, of the shorter 0.08.

_Habitat._--North Pacific, Station 241, depth 2300 fathoms.

2. _Ellipsostylus avicularis_, n. sp.

Proportion of the major axis to the minor = 3 : 2. Shell thick walled, with regular, rosette-shaped meshes, three times as broad as the bars; ten to twelve on the half equator. Every mesh on the outer margin with five to six rounded lobes, as in _Xiphostylus phasianus_ (Pl. 13, fig. 9). Surface smooth. Polar spines sharp edged, thick; the longer straight and equal to the longer axis, the shorter half as long, shaped like a bird's head.

_Dimensions._--Longer axis 0.18, shorter axis 0.12; pores 0.015, bars 0.005.

_Habitat._--South Pacific, Station 300, depth 1375 fathoms.

{300}3. _Ellipsostylus psittacus_, n. sp. (Pl. 13, fig. 6).

Proportion of the major axis to the minor = 4 : 3. Shell thin walled, with regular or subregular rosette-shaped meshes, twice as broad as the bars; eight to nine on the half equator; each mesh with three to four rounded lobes. Surface smooth. Polar spines sharp edged, very unequal; longer spine about twice as long as the major axis, somewhat curved; shorter spine scarcely longer than the radius, shaped like a bird's head.

_Dimensions._--Longer axis 0.08, shorter axis 0.06; pores 0.01, bars 0.005; length of the polar spines--longer 0.15, shorter 0.05.

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

4. _Ellipsostylus aquila_, n. sp. (Pl. 13, fig. 1).

Proportion of the major axis to the minor = 7 : 6. Shell thick walled, with subregular, circular meshes, five to six times as broad as the bars; ten to twelve on the half equator. Surface smooth. Polar spines sharp edged (six-sided?), very unequal; longer spine straight, about equal to the minor axis; shorter spine obliquely inserted, scarcely half as long, shaped like a bird's head.

_Dimensions._--Longer axis 0.15, shorter axis 0.13; pores 0.02, bars 0.004; length of the polar spines--longer 0.1, shorter 0.05.

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

5. _Ellipsostylus columba_, n. sp. (Pl. 13, fig. 3).

Proportion of the major axis to the minor = 4 : 3. Shell egg-shaped, thin walled, with regular, circular meshes, three times as broad as the bars; ten to twelve on the half equator. Surface somewhat thorny. Polar spines nearly of equal length (equal to the major axis), but of very different form; one straight, pyramidal, and obliquely inserted, the other like a bird's head.

_Dimensions._--Longer axis 0.08, shorter 0.06; pores 0.003, bars 0.01; length of the spines 0.09.

_Habitat._--South Atlantic, Station 332, surface.

6. _Ellipsostylus ciconia_, n. sp. (Pl. 13, fig. 8).

Proportion of the major axis to the minor = 7 : 5. Shell egg-shaped, thick walled; the meshes very small, regular, circular, three times as broad as the bars; sixteen to twenty on the half equator. Surface uneven. Polar spines nearly cylindrical, pointed; the smaller obliquely inserted, equal to the major axis; the larger more than twice as long and thick, furrowed at its base. (Compare with this and the allied species _Rhabdolithis pipa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. i. fig. 27.)

_Dimensions._--Longer axis 0.07, shorter 0.05; pores 0.003, bars 0.001; length of the polar spines--longer 0.2, shorter 0.08.

_Habitat._--North Pacific, Station 253, depth 3125 fathoms.

{301}Subgenus 2. _Ellipsostylissa_, Haeckel.

_Definition._--Network of the shell irregular, with pores of different size or form.

7. _Ellipsostylus megadictya_, Haeckel.

_Stylosphæra megadictya_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 299, Taf. viii. fig. 13.

Proportion of the major axis to the minor = 5 : 4. Shell thin walled, with irregular, roundish, large meshes, four to five times as broad as the bars; only four to five on the half equator. Surface smooth. Polar spines straight, thin, angular; the shorter equal to the minor axis, the longer four times as large.

_Dimensions._--Longer axis 0.05, shorter axis 0.04; meshes 0.01, bars 0.002; length of the polar spines--longer 0.12, shorter 0.03.

_Habitat._--Philippine Sea, 3300 fathoms, Ehrenberg.

8. _Ellipsostylus gallinula_, n. sp.

Proportion of the major axis to the minor = 3 : 2. Shell thick walled, with irregular, roundish meshes, twice to four times as broad as the bars; eight to ten on the half equator. Surface thorny. Polar spines conical, straight; the longer twice as long as the major axis, the minor scarcely half as long.

_Dimensions._--Longer axis 0.15, shorter 0.12; pores 0.01 to 0.02, bars 0.002 to 0.004.

_Habitat._--North Pacific, Station 253, surface.

9. _Ellipsostylus hirundo_, n. sp. (Pl. 13, fig. 2).

Proportion of the major axis to the minor = 4 : 3. Shell thick walled, with irregular, roundish meshes, three to five times as broad as the bars; eight to ten on the half equator. The inner aperture of every mesh is fenestrated by a delicate lamella of silex, perforated by six to eight very small circular pores. Polar spines sharp edged, more or less curved, the shorter equal to the minor axis, the longer twice as long.

_Dimensions._--Longer axis 0.16, shorter 0.12; pores 0.01 to 0.02, bars 0.003 to 0.006; length of the polar spines--longer 0.24, shorter 0.12.

_Habitat._--Pacific, central area, Station 268, depth 2900 fathoms; the same form also fossil in the rocks of Barbados.

Genus 128. _Lithomespilus_,[167] Haeckel, 1881, Prodromus, p. 450.

_Definition._--#Ellipsida# with simple ellipsoidal or oviform shell, the main axis of which bears at one pole a single spine, at the other a bunch of several spines.

{302}The genus _Lithomespilus_ differs from the closely allied _Ellipsoxiphus_ in the further differentiation of both poles of the main axis. One pole exhibits only a single polar spine, the other pole a group of several spines, peculiarly grouped together. It differs from the similar _Sphæromespilus_ (Pl. 14, figs. 12, 13) in the ellipsoidal form of the shell.

1. _Lithomespilus phloginus_, n. sp. (Pl. 14, fig. 16).

Proportion of the major axis of the ellipsoid to the minor = 4 : 3. Shell thick walled, with circular pores of different size, the breadth of which equals that of the bars; twelve to fifteen pores on the half equator. Surface smooth, with the exception of a circumpolar region covered with numerous thick spines of unequal size, which surround the large single polar spine and are curved like a bow against its axis. This larger polar spine is straight, and equals in length the major axis of the shell. The other and opposite polar spine is scarcely one-fourth as long, perfectly simple, very stout, and of a three-sided pyramidal shape.

_Dimensions._--Longer axis of the ellipsoidal shell 0.08, shorter axis 0.06; pores 0.002 to 0.006, bars 0.003 to 0.005; length of the polar spines--longer 0.08, shorter 0.02.

_Habitat._--Indian Ocean, near Madagascar, depth 1200 fathoms, Smith.

2. _Lithomespilus phlogoides_, n. sp. (Pl. 14, fig. 17).

Proportion of the major axis to the minor = 5 : 4. Shell very thick walled, with roundish, double-contoured pores of different size and form, twice to three times as broad as the bars; sixteen to eighteen pores on the half equator. Surface smooth, with the exception of a circumpolar region covered with numerous thin spines of unequal size, which surround the large single polar spine and are curved like a bow against its axis. This larger polar spine is straight, and equals half the size of the major axis of the shell; the other polar spine (sometimes double, as in the figured specimen) is much shorter, being scarcely one-fourth as long.

_Dimensions._--Longer axis of the shell 0.08, shorter axis 0.065; pores 0.003 to 0.006, bars 0.002 to 0.004; length of the polar spines--longer 0.04, shorter 0.01.

_Habitat._--Central area of the Pacific, Stations 270 to 272, depth 2425 to 2925 fathoms.

3. _Lithomespilus flammeus_, n. sp.

_Stylosphæra species_, Bury, 1862, Polycystins of Barbados, pl. xi. fig.
3.

Proportion of the major axis to the minor = 4 : 3. Shell thick walled, with irregular, roundish pores, about as broad as the bars; ten to twelve pores on the half equator. Surface spiny. Length of the conical straight spines increasing towards the poles; each polar spine surrounded by a circumpolar group of larger, somewhat curved spines. The larger polar spine equals in length the major axis; the smaller is scarcely half as long. (The figure, given by Bury, is not quite exact; there the spines are situated in the pores, instead of between them. In my specimen the polar spines were not branched.)

{303}_Dimensions._--Longer axis of the shell 0.12, shorter axis 0.09; pores and bars 0.004 to 0.006; length of the polar spines--longer 0.12, shorter 0.06.

_Habitat._--Fossil in Barbados.

4. _Lithomespilus flammabundus_, n. sp. (Pl. 14, fig. 14).

Proportion of the major axis to the minor = 4 : 3. Shell thin walled, with irregular, roundish pores, partly simple, partly composed of three to six confluent pores; only six to eight pores on the half equator, twice to four times as broad as the bars. Surface spiny. Length of the conical irregular spines increasing towards the poles; each polar spine surrounded by a flame-shaped, circumpolar area of longer spines; all large spines (also the polar spines) curved or contorted at one pole and much stronger and more numerous than at the other; length variable, often equal to the longer axis.

_Dimensions._--Longer axis of the shell 0.12, shorter axis 0.09; pores 0.005 to 0.015, bars 0.003 to 0.005; length of the polar spines 0.1 to 0.15.

_Habitat._--Western part of the Tropical Atlantic, Station 347, depth 2250 fathoms.

Genus 129. _Lithapium_,[168] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal or pear-shaped shell; with a single spine only situated at one pole of the main axis.

The genus _Lithapium_ represents a peculiar modification of _Ellipsoxiphus_; one of the two opposite polar spines disappears by reduction, and in this way only a single spine remains, at one pole of the main axis. For this reason the shell assumes a characteristic pear-shape, and may easily be confounded with some similar Monocyrtida (_Halicapsa_).

1. _Lithapium pyriforme_, n. sp. (Pl. 14, fig. 9).

Proportion of the longer axis to the shorter = 6 : 5. Shell thin walled, with regular, circular pores, four times as broad as the bars; six to eight on the half equator. Surface a little thorny. The single polar spines three-sided pyramidal, as broad at the base as one mesh, about as long as the radius of the shell. (In the specimen figured, there was on the opposite pole a little rudiment of the other lost polar spine; it is missing in other specimens.)

_Dimensions._--Major axis of the ellipsoidal shell 0.12, minor axis 0.1; pores 0.02, bars 0.005; length of the single polar spine 0.05, basal thickness 0.02.

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

2. _Lithapium halicapsa_, n. sp. (Pl. 14, fig. 8).

Proportion of the longer axis to the shorter = 6 : 5. Shell thin walled, with irregular, lobed meshes, six to eight on the half equator, twice to five times as broad as the bars; each mesh {304}composed of two to five confluent roundish pores. Surface a little thorny. The single polar spine pyramidal, as broad at the base as one mesh, one-third as long as the axis.

_Dimensions._--Major axis 0.12, minor axis 0.1; pores 0.01 to 0.02, bars 0.002 to 0.006; length of the single polar spine 0.03, basal thickness 0.02.

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

3. _Lithapium monocyrtis_, n. sp. (Pl. 14, fig. 10).

Proportion of the longer axis to the shorter = 7 : 6. Shell thick walled, with irregular, lobed meshes, four to six on the half equator, three to six times as broad as the bars; each mesh composed of three to six confluent roundish pores. Surface quite smooth, without thorns. The single polar spine pyramidal, as broad at the base as the largest mesh, half as long as the radius. (This species is closely allied to the foregoing, but differs in the smooth surface and the larger meshes.)

_Dimensions._--Major axis 0.15, minor axis 0.13; pores 0.01 to 0.03, bars 0.003 to 0.01; length of the single spine 0.04, basal thickness 0.03.

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

Genus 130. _Pipettella_,[169] n. gen.

_Definition._--#Ellipsida# with simple ellipsoidal shell, the main axis of which is prolonged at the pole into two opposite hollow fenestrated tubes of equal size and similar form.

The genus _Pipettella_ is distinguished from the other Ellipsida by two hollow perforated tubes, which are directed in the longer axis of the ellipsoidal shell and arise from opposite poles of this axis. It may be derived from _Cenellipsis_ by prolongation of both poles of the main axis. As the same peculiar production of two opposite latticed tubuli at the poles of the main axis obtains in nearly all families of #Prunoidea# (_Pipetta_, _Cannartus_, _Panarium_, _Zygartus_, &c.), it may possess a peculiar value in this group.

1. _Pipettella fusiformis_, n. sp.

Shell spindle-shaped, thin walled, the two opposite tubes being conical and not longer than the short transverse axis of the ellipsoidal shell; no sharp demarcation between them. The two axes of the ellipsoid bear the proportion of 3 : 2. Network of the shell and of the tubes equal, delicate, regular, hexagonal, with circular apertures of equal size; fourteen to sixteen on the half equator of the shell. Bars very thin. The shell of this species is similar to that of _Cannartiscus amphiconiscus_ (Pl. 39, fig. 19), but possesses no equatorial stricture and no medullary shell.

_Dimensions._--Longer axis of the ellipsoid 0.18, shorter axis 0.12; length of the tubes 0.1, their basal breadth 0.05; pores of the network 0.01, bars 0.001.

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

{305}2. _Pipettella tubulosa_, n. sp.

Shell ellipsoidal, thin walled, distinctly separated from the two opposite tubes, which are cylindrical, longer than the main axis of the ellipsoid, and one-sixth as broad as the shorter axis. The longer axis of the ellipsoid bears to the shorter the proportion of 5 : 4. Network of the shell and of the tubes equal, regular, with very small circular pores, about as broad as the bars; sixteen to eighteen pores on the half equator of the shell.

_Dimensions._--Longer axis of the ellipsoid 0.15, shorter axis 0.12; length of the tubes 0.16 to 0.2, breadth of them 0.02; pores of the network 0.003, bars 0.003.

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

3. _Pipettella elongata_, n. sp.

Shell ellipsoidal, thick walled, distinctly separated from both opposite tubes, which are cylindrical, much prolonged, twice to three times as long as the main axis of the ellipsoid, and one-fifth as broad as the shorter axis. Both axes of the ellipsoid bear the proportion of 3 : 2. Network of the shell and of the tubes irregular with small rounded pores of different size, separated by broader bars (often twice to three times as broad), four to six pores on the half equator of the shell. (This species somewhat recalls _Solenosphæra serpentina_, Pl. 7, fig. 7; but the tubes are straight, not contorted.)

_Dimensions._--Longer axis of the ellipsoid 0.2, shorter axis 0.14; length of the tubes 0.4 to 0.5, breadth 0.03; pores of the network 0.001 to 0.002, bars 0.003 to 0.004.

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

4. _Pipettella prismatica_, n. sp. (Pl. 39, fig. 6).

Shell ellipsoidal, thick walled, distinctly marked off from the two opposite tubes, which are longer than its main axis and as broad as one-fifth of it; they are nearly four-sided prismatic, with four strong ribs or edges; these are directed parallel to the main axis, in two meridian planes, perpendicular to one another. The wall of the shell is thickened in the equatorial plane, so as to form a slight stricture on the inside, separating its two halves. Both axes of the ellipsoid bear the proportion of 7 : 6. Network regular, with circular pores, somewhat broader than the bars. The meshes of the shell (fourteen to sixteen on the half equator) are twice as great as those of the tubes, which are arranged in two longitudinal rows between every two ribs (there being eight longitudinal rows on the whole tube). This species is very remarkable for the rudimentary internal equatorial stricture of the shell (transition to the genus _Cannartus_, Pl. 39, fig. 10), and by the four edges of the tubes, which indicate two of the dimensive axes, the third being represented by the main axis.

_Dimensions._--Longer axis of the ellipsoid 0.14, shorter axis 0.12; length of the tubes 0.15 to 0.16, breadth 0.03; pores of the shell 0.008 to 0.01, pores of the tubes 0.004.

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

{306}Family XII. #DRUPPULIDA#, Haeckel, 1882 (Pls. 15, 16, 17, 39).

_Definition._--#Prunoidea# with ellipsoidal, latticed (not spongy) shell, composed of two or more concentric shells; a simple or double cortical shell enclosing one or two internal concentric shells (medullary shells), without equatorial stricture. Central capsule ellipsoidal or cylindrical, without annular equatorial constriction.

The family #Druppulida# differs from the Ellipsida only in the possession of a simple or double medullary shell, which is enclosed in the centre of the central capsule, and connected with the ellipsoidal cortical shell (lying outside it) by radial beams, perforating the membrane of the capsule. The Druppulida exhibit therefore the same relation to the Ellipsida that the Dyosphærida among the #Sphæroidea# bear to the Monosphærida. The cortical shell may be simple or multiple. The whole fenestrated shell is thus composed of a variable number (two at least) of concentric shells, which are connected by radial beams.

_The Medullary Shell_--enclosed in the centre of the central capsule--is either simple or double, and composed of two small concentric shells. Their form is either spherical, or ellipsoidal, or lenticular. If the medullary shell be ellipsoidal, the main axis of the ellipsoid is the same as in the cortical shell. Sometimes the inner medullary shell is spherical, the outer ellipsoidal or lenticular. If the medullary shell be lenticular (arising from both poles of the main axis) its vertical axis is also identical with that of the cortical shell (Pl. 39, fig. 5).

_The Radial Beams_, which connect the medullary and cortical shell, are either developed in all possible directions (Pls. 16, 17), or limited to the equatorial plane, more rarely to the meridional plane. Sometimes the connection is produced only by two opposite beams which lie in the minor or equatorial axis (Pl. 39, figs. 3, 7, 8); more rarely in the major or meridional axis (Pl. 17, figs. 7, 8).

_The Cortical Shell_ is constantly ellipsoidal, rarely with modifications, similar to those which appear in the simple shell of some Ellipsida. As a rule it is simple, rarely composed of two or more (sometimes six or more) concentric ellipsoidal shells (in _Cromyodruppa_ and _Cromyocarpus_). The outer surface is commonly smooth, more rarely covered with radial spines (in _Druppocarpus_, _Prunocarpus_, &c.). In the majority peculiar polar appendages are developed at both poles of the main axis, these being prolongations of them, either in the form of hollow fenestrated tubes (_Pipetta_, _Pipettaria_, Pl. 39, figs. 7, 8), or solid strong spines. The two polar spines are either equal in size and similar in form (as in _Lithatractus_, _Stylatractus_) or unequal (as in _Druppatractus_, _Xiphatractus_, Pls. 16, 17).

The most primitive of all Druppulida is _Druppula_, with simple medullary shell and simple cortical shell (Pl. 39, fig. 3); _Prunulum_ differs from it only in the possession {307}of a double medullary shell (Pl. 39, fig. 4). From these two genera all other forms of the subfamily may be derived.

_The Central Capsule_ of the Druppulida is constantly ellipsoidal, larger than the concentric enclosed medullary shells, smaller than the surrounding cortical shell; it is separated from the inner surface of the latter by a thinner or thicker jelly-mantle.

_Synopsis of the Genera of the Druppulida._

-------------------------------------------------------------------------
Cortical shell without polar appendages (neither solid spines nor hollow
tubes at the poles of the main axis).
-------------------------------------------------------------------------
{ {Surface
{Medullary { smooth, 131. _Druppula_.
{ shell simple.{
{ {Surface
Cortical shell { { spiny, 132. _Druppocarpus_.
simple, {
ellipsoidal. { {Surface
{Medullary { smooth, 133. _Prunulum_.
{ shell double.{
{ {Surface
{ { spiny, 134. _Prunocarpus_.

Cortical shell }Medullary {Surface
composed of } shell { smooth, 135. _Cromyodruppa_.
two or more } double. {
concentric } {Surface
shells. } { spiny, 136. _Cromyocarpus_.
-------------------------------------------------------------------------
Two opposite solid spines, arising from the poles of the main axis.
-------------------------------------------------------------------------
{ {Both polar
{Medullary { spines equal, 137. _Lithatractus_.
{ shell {
{ simple. {Both polar
Cortical { { spines
shell { { unequal, 138. _Druppatractus_.
simple, {
ellipsoidal.{ {Both polar
{ { spines equal, 139. _Stylatractus_.
{Medullary {
{ shell {Both polar
{ double. { spines
{ { unequal, 140. _Xiphatractus_.

Cortical shell composed of two or more
concentric shells; medullary shell
double; both polar spines equal, 141. _Cromyatractus_.
-------------------------------------------------------------------------
Two opposite hollow fenestrated tubes, arising from the poles of the
main axis.
-------------------------------------------------------------------------
Medullary shell simple, 142. _Pipetta_.

Medullary shell double, 143. _Pipettaria_.

Genus 131. _Druppula_,[170] n. gen.

_Definition._--#Druppulida# with simple ellipsoidal, cortical shell, and simple medullary shell, without spines or polar tubes.

The genus _Druppula_, as the simplest form of the Druppulida, may be regarded as the common ancestral form of this subfamily. It may be derived phylogenetically either {308}from _Carposphæra_ by prolongation of one axis, or from _Cenellipsis_ by duplication of the fenestrated shell. The outer (or cortical) shell is always more or less ellipsoidal; the inner (or medullary) shell also is sometimes ellipsoidal, sometimes spherical. Both shells are concentric, connected by a variable number of radial beams. Compare _Haliomma oblongum_, Harting, 1863, L. N. 18, p. 15, pl. 2, fig. 42.

Subgenus 1. _Druppuletta_, Haeckel.

_Definition._--Pores of the cortical shell regular, hexagonal, or circular.

1. _Druppula drupa_, n. sp.

Cortical shell thin walled, with smooth surface and regular network; both its axes bear the proportion of 4 : 3. Pores regular, hexagonal, three times as broad as the bars; twelve to fifteen on the half equator. Medullary shell spherical, about one-third as broad as the cortical shell.

_Dimensions._--Major axis of the ellipsoidal cortical shell 0.1 to 0.12, minor axis 0.08 to 0.09; pores 0.06, bars 0.02; diameter of the medullary shell 0.03.

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

2. _Druppula pandanus_, n. sp. (Pl. 39, fig. 3).

Cortical shell thin walled, somewhat rough, with regular network; both its axes bear the proportion of 3 : 2. Pores subregular, circular, hexagonally framed, one and a half times as broad as the elevated bars; ten to twelve on the half equator. Medullary shell spherical, one-fourth as broad as the cortical shell.

_Dimensions._--Major axis of the cortical shell 0.16 to 0.17, minor axis 0.11 to 0.12; pores 0.01, bars 0.007; diameter of the medullary shell 0.035.

_Habitat._--Pacific, central area, Station 268, depth 2900 fathoms.

3. _Druppula cocos_, n. sp.

Cortical shell thick walled, somewhat rough, with regular network; proportion of both axes = 6 : 5. Pores regular, circular, hexagonally framed, quite as broad as the elevated bars; fourteen to sixteen on the half equator. Medullary shell ellipsoidal (with longitudinal main axis), nearly half as large as the cortical shell.

_Dimensions._--Major axis of the cortical shell 0.07 to 0.08, minor axis 0.6 to 0.65; pores and bars 0.003 to 0.004; diameter of the medullary shell 0.03 and 0.035.

_Habitat._--Western Tropical Pacific, Station 222, surface, Indian Ocean, Ceylon, Haeckel.

4. _Druppula phoenix_, n. sp.

Cortical shell thick walled, smooth, with regular network; proportion of both axes = 5 : 4. Pores regular, circular, hexagonally lobulate (in the same manner as in _Stauroxiphus gladius_, {309}Pl. 15, fig. 7), three times as broad as the bars; ten to twelve on the half equator. Medullary shell ellipsoidal (with longitudinal main axis), one-third as broad as the cortical shell.

_Dimensions._--Major axis of the cortical shell 0.1, minor axis 0.08; pores 0.009, bars 0.003; axis of the medullary shell 0.03 and 0.025.

_Habitat._--Mediterranean, Smyrna, Haeckel, surface.

5. _Druppula areca_, n. sp.

Cortical shell thin walled, with smooth surface and regular network; both its axes bear the proportion of 4 : 3. Pores regular, circular, four times as broad as the bars; fifteen to eighteen on the half equator. Medullary shell spherical, half as broad as the cortical shell.

_Dimensions._--Major axis of the ellipsoidal cortical shell 0.12 to 0.14, minor axis 0.1 to 0.11; pores 0.008, bars 0.002; diameter of the medullary shell 0.05 to 0.06.

_Habitat._--Indian Ocean, off Bombay, Haeckel.

6. _Druppula ovata_, Haeckel.

_Haliomma ovatum_, Ehrenberg, 1854, Mikrogeol., pl. xx. I. fig. 20.

_Haliomma ovatum_, Haeckel, 1862, Monogr. d. Radiol., p. 432.

Cortical shell thin walled, with smooth surface and regular network; proportion of both axes = 3 : 2. Pores regular, circular, three times as broad as the bars; nine to ten on the half equator. Medullary shell spherical, one-third as broad as the cortical shell.

_Dimensions._--Major axis 0.08 to 0.1, minor axis 0.05 to 0.06; pores 0.003, bars 0.001; diameter of the medullary shell 0.02.

_Habitat._--Fossil in the Tertiary rocks of the Mediterranean coast, Greece (Zante), Ehrenberg; Sicily (Caltanisetta), Haeckel.

7. _Druppula caryota_, n. sp.

Cortical shell thick walled, with rough surface and regular network; proportion of both axes = 5 : 4. Pores regular, circular, twice as broad as the bars; sixteen to twenty on the half equator. Medullary shell ellipsoidal, one-third as large as the cortical shell.

_Dimensions._--Major axis 0.2 to 0.22, minor 0.16 to 0.18, pores 0.008, bars 0.004; axes of the medullary shell 0.07 and 0.055.

_Habitat._--Pacific, central area, Stations 266 to 268, depth 2700 to 2900 fathoms.

Subgenus 2. _Druppulissa_, Haeckel.

_Definition._--Pores of the cortical shell irregular, of different form or size, usually subcircular or roundish, sometimes lobed or compound.

{310}8. _Druppula nucula_, n. sp.

Cortical shell thin walled, smooth, with irregular network; its two axes bear the proportion 3 : 2. Pores subcircular or irregular, roundish, twice to four times as broad as the bars; fifteen to twenty on the half equator. Medullary shell spherical, about one-third as broad as the cortical shell.

_Dimensions._--Major axis of the cortical shell 0.15 to 0.2, minor axis 0.1 to 0.14; pores 0.006 to 0.012, bars 0.03; diameter of the medullary shell 0.04.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.

9. _Druppula elliptica_, Haeckel.

_Haliomma ellipticum_, Stöhr, 1880, Palæontogr., _loc. cit._, p. 88, Taf.
i. fig. 11.

Cortical shell thin walled, rough, or thorny, with irregular network; proportion of the axes = 3 : 2. Pores subcircular or irregular, roundish, about as broad as the bars; ten to twelve on the half equator. Medullary shell half as broad as the cortical shell, irregularly polyhedral (with crooked beams in its interior).

_Dimensions._--Major axis 0.15, minor 0.06; pores and bars 0.006; diameter of the medullary shell 0.03.

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

10. _Druppula prunum_, n. sp.

Cortical shell thick walled, smooth, with irregular network; proportion of the axes = 5 : 4. Pores subcircular or irregular, roundish, three to four times as broad as the bars; seven to eight on the half equator; every pore is closed at the bottom by a thin membrane, perforated by four to six irregular pores (like _Stylatractus sethoporus_, Pl. 17, fig. 3). Medullary shell spherical, one-third as broad as the cortical shell.

_Dimensions._--Major axis 0.2, minor axis 0.16; pores 0.03, bars 0.01; small enclosed porules 0.01; diameter of the medullary shell 0.05.

_Habitat._--Mediterranean, surface, Portofino near Genoa, Haeckel.

11. _Druppula oliva_, n. sp.

Cortical shell thick walled, rough, with irregular network; proportion of the axes = 5 : 4. Pores irregular, roundish, three to four times as broad as the bars; lobed or composed of several conjugated porules (as in _Lithapium halicapsa_, Pl. 14, fig. 8); five to six large pores on the half equator. Medullary shell ellipsoidal, about one-third as broad as the cortical shell.

_Dimensions._--Major axis of the cortical shell 0.15, minor 0.12; pores 0.02 to 0.03, bars 0.007; diameter of the medullary shell 0.04.

_Habitat._--Mediterranean (Corfu), Canary Islands (Lanzerote), Haeckel.

{311}Genus 132. _Druppocarpus_,[171] n. gen.

_Definition._--#Druppulida# with simple ellipsoidal cortical shell and simple medullary shell, with numerous radial spines, without polar tubes.

The genus _Druppocarpus_ differs from _Druppula_ only in the radial spines, which arise between the pores of the cortical shell, and therefore exhibits the same relation to it that _Ellipsidium_ bears to _Cenellipsis_, or _Prunocarpus_ to _Prunulum_.

Subgenus 1. _Druppocarpetta_, Haeckel.

_Definition._--Network of the cortical shell regular, with meshes of equal size and similar form.

1. _Druppocarpus ananassa_, n. sp.

Cortical shell thin walled, with regular, circular, hexagonally framed pores, of about the same breadth as the elevated bars; fourteen to sixteen on the half equator. From each hexagon-corner (between every three pores) arises a short thin radial spine, about as long as two pores, three-sided pyramidal at the base. Proportion of both cortical axes = 4 : 3. Medullary shell spherical, half as broad as the cortical shell. (Greatly resembles _Druppula pandanus_, Pl. 39, fig. 3, but differs in the larger medullary shell and the spines on the surface.)

_Dimensions._--Major axis of the ellipsoidal cortical shell 0.16, minor 0.12; pores and bars 0.006; length of the radial spines 0.02; diameter of the medullary shell 0.06.

_Habitat._--South Pacific, Station 289, surface.

2. _Druppocarpus castanea_, n. sp.

Cortical shell thin walled, with regular circular pores (without hexagonal frames), of about the same breadth as the bars; twelve to fourteen on the half equator. Between every three meshes arise a short conical spine with bristle-like apex, twice to four times as long as one pore. Proportion of both cortical axes = 3 : 2. Medullary shell spherical, one-third as broad as the cortical. (Resembles very closely the spherical _Haliomma castanea_, Haeckel, figured in my Monograph. pl. xxiv. fig. 4.)

_Dimensions._--Major axis 0.15, minor axis 0.1; pores and bars 0.005; length of the radial spines 0.01 to 0.02; medullary shell 0.035.

_Habitat._--North Atlantic, surface; Canary Islands, Lanzerote, Haeckel.

Subgenus 2. _Druppocarpissa_, Haeckel.

_Definition._--Network of the cortical shell irregular, with meshes of different size or form.

{312}3. _Druppocarpus chamaerops_, n. sp.

Cortical shell thin walled, with irregular, roundish, or subcircular pores of very different size, twice to six times as broad as the thin bars; eight to twelve on the half equator. Between them arise numerous thin, bristle-like radial spines, about half as long as the equatorial axis, and equal to the diameter of the spherical medullary shell; pores of the latter subregular, circular, very small. (Resembles _Prunocarpus artocarpus_, Pl. 39, fig. 5, but differs in the simple spherical medullary shell.)

_Dimensions._--Major axis 0.12, minor 0.09; meshes 0.005 to 0.02, bars 0.003; length of the radial spines 0.05; diameter of the medullary shell 0.04.

_Habitat._--Mediterranean, in the Strait of Gibraltar, Algesiras, Haeckel, surface.

4. _Druppocarpus borassus_, n. sp.

Cortical shell thick walled, with irregular, roundish, or subcircular pores, three to five times as broad as the bars; twelve to fifteen on the half equator. Irregularly scattered on the surface about twenty to thirty short conical spines; their length equals their basal breadth and the diameter of the largest pores. Medullary shell ellipsoidal, half as large as the cortical.

_Dimensions._--Major axis 0.1, minor 0.08; pores 0.006 to 0.01, bars 0.002; length and thickness of the radial spines 0.01; axes of the medullary shell 0.05 and 0.04.

_Habitat._--Pacific, central area, Station 268, depth 2900 fathoms.

5. _Druppocarpus corypha_, n. sp.

Cortical shell thick walled, with irregular, funnel-like, roundish pores, scarcely as broad as the bars; sixteen to twenty on the half equator. Irregularly scattered on the surface about fifteen to twenty three-sided pyramidal radial spines, half as long as the equatorial axis, and as the diameter of the medullary shell.

_Dimensions._--Major axis 0.17, minor 0.14; pores and bars 0.003 to 0.009; length of the radial spines 0.08; diameter of the medullary shell 0.09.

_Habitat._--Fossil in the Tertiary rocks of the Nicobars, Haeckel.

Genus 133. _Prunulum_,[172] n. gen.

_Definition._--#Druppulida# with simple ellipsoidal cortical shell and double medullary shell; without spines or polar tubes.

The genus _Prunulum_ differs from _Druppula_ in the double (not simple) medullary shell, which is sometimes spherical, sometimes ellipsoidal; it may be derived either from _Druppula_ by duplication of the medullary shell, or from _Thecosphæra_ by prolongation of one axis.

{313}Subgenus 1. _Prunuletta_, Haeckel.

_Definition._--Network of the cortical shell regular, with meshes of equal size and similar form.

1. _Prunulum frugulum_, n. sp.

Cortical shell thin walled, smooth, with regular, hexagonal pores, three times as broad as the bars; ten to twelve on the half equator. Proportion of the major axis of the ellipsoid to the minor = 4 : 3. Both medullary shells spherical. (Differs from _Druppula drupa_ almost entirely in the double medullary shell.)

_Dimensions._--Major axis of the ellipsoidal cortical shell 0.12, minor 0.09; pores 0.006, bars 0.002; diameter of both medullary shells 0.05 and 0.03.

_Habitat._--Pacific, central area, Station 266, depth 2750 fathoms.

2. _Prunulum cerasum_, n. sp.

Cortical shell thick walled, smooth, with circular, hexagonally framed pores, of the same breadth as the bars; sixteen to eighteen on the half equator. Proportion of the two axes of the ellipsoid = 5 : 4. Both medullary shells spherical. (The cortical shell resembles that of _Pipetta tuba_, Pl. 39, fig. 7, without the polar tubes.)

_Dimensions._--Major axis 0.15, minor 0.12; pores and bars 0.007; diameter of the medullary shells 0.08 and 0.04.

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

3. _Prunulum amygdalum_, n. sp.

Cortical shell thick walled, smooth, with regular, circular, hexagonally lobulated pores, three times as broad as the bars; twelve to fourteen on the half equator (of the same form as in _Druppula phoenix_ and in _Stauroxiphos gladius_, Pl. 15, fig. 7). Proportion of the two axes = 6 : 5. Inner medullary shell spherical, outer ellipsoidal.

_Dimensions._--Major axis 0.12, minor 0.1; pores 0.009, bars 0.003; diameter of the medullary shells 0.07 and 0.04.

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

4. _Prunulum coccymelium_ (Pl. 39, fig. 4).

Cortical shell thin walled, slightly rough, with regular, circular pores, twice as broad as the bars; twelve to fifteen on the half equator. Proportion of both axes = 4 : 3. Both medullary shells spherical.

_Dimensions._--Major axis 0.12, minor 0.09; pores 0.006, bars 0.003; diameter of the medullary shells 0.06 and 0.03.

_Habitat._--Pacific, central area, Station 273, depth 2350 fathoms.

{314}5. _Prunulum crenatum_, Haeckel.

? _Haliomma crenatum_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 36.

_Actinomma crenatum_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 94, Taf.
iii. fig. 3.

_Caryolithis crenata_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 43.