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.

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 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.

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 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 phœnix, 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, 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.

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.

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.

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.

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.

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.

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 phœnix 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.

5. Prunulum crenatum, Haeckel.

Cortical shell thick walled, slightly rough or thorny, with small, regular, circular pores, of the same breadth as the bars; sixteen to eighteen on the half equator. Proportion of the two axes = 4 : 3. Both medullary shells ellipsoidal. (The figure of Stöhr represents exactly the fossil form, as I have observed it myself in the Caltanisetta rocks, whilst the figure of Ehrenberg is inaccurate and doubtful. The same form, somewhat variable in size and in the number of the pores, I have also observed in the Pacific ooze.)

Dimensions.—Major axis 0.14 to 0.17, minor 0.1 to 0.13; pores and bars 0.006; main axes of the medullary shells 0.09 and 0.03.

Habitat.—Fossil in the Tertiary rocks of Sicily (Grotte and Caltanisetta); living in the Central Pacific, Station 268, depth 2900 fathoms.

6. Prunulum triplex, Haeckel.

Cortical shell thin walled, covered with numerous very thin, short, bristle-like spines. Pores small, regular, circular, of the same breadth as the bars; fourteen to sixteen on the half equator. Proportion of the two axes = 3 : 2. Both medullary shells ellipsoidal. The description of Ehrenberg—as is very often the case—is quite incongruent with his figure. From a combination of both I give here the diagnosis of a deep-sea species, which is possibly identical with it. The velvet-like covering of very short and thin bristles is peculiarly characteristic of this species.

Dimensions.—Major axis 0.1, minor 0.065; pores and bars 0.004; main axes of the medullary shells 0.04 and 0.02.

Habitat.—North Atlantic, 1800 fathoms, Ehrenberg; Station 353, depth 2965 fathoms.

Subgenus 2. Prunulissa, Haeckel.

Definition.—Network of the cortical shell irregular, with meshes of different form or size (usually roundish, but sometimes lobed or compound).

7. Prunulum persicum, n. sp.

Cortical shell thick walled, with smooth surface and irregular, roundish, double-contoured pores, twice to four times as broad as the bars; eight to ten on the half equator. Some of the pores are simple, often subcircular, others lobed, i.e., composed of from two to three confluent pores as in Amphisphæra pluto (Pl. 17, fig. 7). Proportion of the two axes = 3 : 2. Both medullary shells ellipsoidal (or the inner spherical).