Family XLII. Belonaspida, n. fam. (Pl. , figs. 6-9; Pl. , figs. 8, 9)

Suborder II. Prunophracta.

Definition.—Shell ellipsoidal, lenticular or diploconical, with radial beams of different size.

Definition.—Acantharia with a simple ellipsoidal lattice-shell, composed of the branched apophyses of twenty radial spines meeting in its centre and disposed according to the Müllerian law of Icosacantha. Two opposite equatorial spines larger than the two others. Central capsule ellipsoidal, enclosed in the fenestrated shell.

The family Belonaspida, formerly united by me with the Dorataspida (in the Prodromus, 1881, p. 468), differs from it in the ellipsoidal form of the lattice-shell and the enclosed central capsule. In the spherical Dorataspida, their ancestral family, all twenty radial spines are of equal size, whilst here in the Belonaspida two opposite spines are larger than the eighteen others. These two larger or principal spines are both equatorial spines, placed in the longitudinal or major axis of the ellipsoid, or the "hydrotomical axis" (compare above, p. ). The two other equatorial spines are constantly smaller, and lie in the transverse or minor axis of the ellipsoid, or the "geotomical axis." The geometrical proportion of these two determining axes of the ellipsoidal shell is very variable (even in one and the same species), commonly 4 : 3 or 3 : 2, rarely 2 : 1, often only 5 : 4 or 6 : 5. All meridian planes, passing through the principal spines (or the longitudinal axis of the shell) are elliptical, and of equal size. All transverse planes, perpendicular to that axis, are circular; the largest of these circular parallel planes is the geotomical plane, which passes through the smaller equatorial spines and the spineless axis.

In the spherical Dorataspida the internal length of the radial spines (or the distance between the shell and the centre) is equal in all twenty spines. In the ellipsoidal Belonaspida this internal length is different, and commonly exhibits four different degrees; in the two principal spines it is of first rank, in the eight tropical spines of second rank, in the four (hydrotomical) polar spines of third rank, and in the six spines (four geotomical polar spines and two transverse equatorial spines) of fourth rank. These differences of the internal length become more important the more the hydrotomical axis is prolonged. Regarding all other qualities (in form, disposition, and mode of junction at the centre) the ellipsoidal Belonaspida do not differ from their ancestral group, the spherical Dorataspida (compare above, p. ). In both families the pyramidal central bases of the twenty spines are commonly supported one upon another with their triangular neighbouring faces; but sometimes also here (particularly in Phatnaspis) the central bases are perfectly grown together. In this case also the sutures of the meeting branches of the apophyses are obliterated, whilst usually they remain open. Such forms, with spines and plates perfectly grown together, form a single piece of acanthin, and were formerly separated by me as a peculiar genus Haliommatidium (Monogr. d. Radiol., 1862, p. 419). But as I now find this concrescence to be an accidental and inconstant peculiarity of some species, it no longer seems to me to be of generic importance.

The apophyses of the twenty radial spines, the branches of which compose the ellipsoidal lattice-shell, exhibit in all Belonaspida the same appearance as in the Diporaspida (and especially the Ceriaspida) among the spherical Dorataspida. Everywhere each radial spine gives off only two opposite primary apophyses, the fork-branches of which unite together and form a plate or shield with two aspinal pores (as in Dorataspis). Commonly the shell exhibits only these forty parmal pores, the other meshes between them being sutural pores. Only in one genus, Phatnaspis (Pl. , figs. 6-9), is this number multiplied; the two opposite primary apophyses are here crossed by numerous perpendicular lateral branches, and these are again united by secondary perpendicular ramules which are parallel to the apophyses themselves; therefore each plate here forms a rhombic shield pierced by very numerous (often more than one hundred) small quadrangular or circular pores. Only two of these numerous parmal pores are the primary aspinal pores (sometimes, as in Pl. , fig. 8, distinguished by their larger size); all others are secondary or coronal pores. Therefore Phatnaspis repeats the characteristic formation of Coscinaspis, from which it differs in its ellipsoidal shell.

Moreover, the four other genera of the ellipsoidal Belonaspida correspond perfectly to certain genera of the spherical Dorataspida, and may be derived from these by hypertrophy or stronger development of two opposite equatorial spines. In Thoracaspis and Belonaspis (Pl. , figs. 8, 9) the surface of the shell-plates is without crests and dimples (in the former without, in the latter with accessory by-spines); they thus correspond to Dorataspis and Diporaspis among the Dorataspida. In two other genera the surface of the shell-plates bears a network of elevated crests, separating funnel-shaped dimples, in Dictyaspis without, in Coleaspis with by-spines; these correspond to Ceriaspis and Hystrichaspis among the Dorataspida. The small by-spines, covering the surface, exhibit the same forms as in the Dorataspida; but they are usually smaller, and less developed in the Belonaspida.

The twenty radial spines are commonly more or less compressed or two-edged, sometimes very flat, broad, and triangular (Pl. , figs. 8, 9). In some species (mainly of Phatnaspis) they are very long, thin, and needle-shaped (Monogr. d. Radiol., 1862, Taf. xxii. figs. 10-12). Rarely they are cylindrical, four-edged, or prismatic. The Belonaspida testify by this and other peculiarities to their near relation to the Diporaspida and Phractacanthida and their older origin from Zygacantha.

The Central Capsule is in the Belonaspida ellipsoidal, and more or less prolonged in the hydrotomical or longitudinal axis of the shell. It is constantly smaller than the enveloping ellipsoidal shell, and separated from it by the calymma. Its structure and the shape of its nucleus are the same as in the nearly allied Dorataspida.

Synopsis of the Genera of Belonaspida.

II. Subfamily Coleaspida.

Forty parmal pores (two aspinal pores on each plate, no coronal pores).

Plates not dimpled, without prominent crests. No by-spines, 371. Thoracaspis.

With by-spines, 372. Belonaspis.

Plates dimpled, with a network of prominent crests, No by-spines, 373. Dictyaspis.

With by-spines, 374. Coleaspis.

II. Subfamily Phatnaspida.

Eighty to two thousand or more parmal pores (two aspinal pores on each plate, surrounded by two to one hundred or more coronal pores).

No by-spines (plates not dimpled), 375. Phatnaspis.

I. Subfamily Coleaspida. Forty parmal pores (two aspinal pores on each plate, no coronal pores).

Plates not dimpled, without prominent crests.

No by-spines,

371. Thoracaspis.

With by-spines,

372. Belonaspis.

Plates dimpled, with a network of prominent crests,

No by-spines,

373. Dictyaspis.

With by-spines,

374. Coleaspis.

II. Subfamily Phatnaspida. Eighty to two thousand or more parmal pores (two aspinal pores on each plate, surrounded by two to one hundred or more coronal pores).

No by-spines (plates not dimpled),

375. Phatnaspis.

Genus 371. Thoracaspis, Haeckel, 1862, Prodromus, p. 468.

Definition.—Belonaspida with forty parmal pores (two on each plate), without dimples and crests, also without by-spines, therefore with smooth surface.

The genus Thoracaspis is the simplest form among the Belonaspida, and repeats in this family the nearly allied genus Dorataspis among the Dorataspida. It differs from this genus only in the characteristic prolongation of one equatorial axis, which effects an ellipsoidal transformation of the spherical central capsule and the enclosing lattice-shell.

1. Thoracaspis ellipsoides, n. sp.

Parmal pores large, elliptical, five or six times as large as the small circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed triangular, sword-like, two-edged; inner and outer half of nearly equal length.

Dimensions.—Length of the ellipsoidal shell (or major axis) 0.15, breadth (or minor axis) 0.12; length of the spines 0.07, basal breadth 0.016.

Habitat.—North Pacific, Station 253, surface.

2. Thoracaspis nephropora, n. sp.

Parmal pores large, kidney-shaped, three to four times as large as the roundish small sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines in the inner longer part cylindrical, in the outer shorter part conical, not compressed.

Dimensions.—Length of the shell 0.2, breadth 0.15; length of the spines 0.06, basal breadth 0.018.

Habitat.—Central Pacific, Station 268, surface.

3. Thoracaspis circopora, n. sp.

Parmal pores circular, of the same size as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, thin, linear, two-edged; outer part one and a half times as long as the inner.

Dimensions.—Length of the shell 0.17, breadth 0.13; length of the spines 0.12, basal breadth 0.003.

Habitat.—South Pacific, Station 288, surface.

4. Thoracaspis bipennis, n. sp. (Pl. , fig. 8).

Parmal pores elliptical, about twice as large as the circular sutural pores, which are of rather variable size. Each plate surrounded by eight to twelve sutural pores (commonly two on each side). Spines compressed, triangular, gradually tapering towards both ends; outer half a little longer, and much broader than the inner.

Dimensions.—Length of the shell 0.14, breadth 0.12; length of the spines 0.08, basal breadth 0.025.

Habitat.—Central Pacific, Station 274, surface.

Genus 372. Belonaspis, Haeckel, 1862, Prodromus, p. 468.

Definition.—Belonaspida with forty parmal pores (two on each plate), without dimples and crests, but with numerous by-spines on the surface.

The genus Belonaspis differs from its ancestral genus Thoracaspis only in the possession of numerous superficial by-spines, and bears therefore to it the same relation as Diporaspis does to Dorataspis. The two latter differ from the two former in the spherical form of the central capsule and the enclosing shell, which here becomes ellipsoidal.

1. Belonaspis pandanus, n. sp.

Parmal pores elliptical, three or four times as large as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, triangular; outer part half as long as the inner, and twice as long as the numerous, simple, bristle-shaped by-spines.

Dimensions.—Length of the ellipsoidal shell (or major axis) 0.12, breadth (or minor axis) 0.1; length of the spines 0.03, basal breadth 0.02.

Habitat.—South Pacific, Station 295, surface.

2. Belonaspis furcata, n. sp.

Parmal pores elliptical, twice as broad as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, linear, very thin; outer part longer than the inner. By-spines very numerous, half as long as the radius, furcate, with divergent fork-branches.

Dimensions.—Length of the shell 0.1, breadth 0.08; length of the spines 0.12, breadth 0.003.

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

3. Belonaspis datura, n. sp. (Pl. , fig. 9).

Parmal pores elliptical, three or four times as large as the circular sutural pores. Each plate surrounded by ten or twelve sutural pores (two on each side). Spines triangular, two-edged, about as long as the radius of the shell; gradually tapering from its surface towards both ends. By-spines very short and numerous, simple.

Dimensions.—Length of the shell 0.13, breadth 0.11; length of the spines 0.08, basal breadth 0.025.

Habitat.—Central Pacific, Station 271, surface.

4. Belonaspis lanceolata, n. sp.

Parmal pores elliptical, six or eight times as large as the small circular sutural pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines lanceolate, flat, in the distal part needle-shaped, about as long as the diameter of the shell. By-spines very numerous, zigzag, half as long as the shell-radius.

Dimensions.—Length of the shell 0.15 breadth 0.13; length of the spines 0.14, basal breadth 0.03; length of the by-spines 0.04.

Habitat.—North Pacific, Station 235, surface.

5. Belonaspis conifera, n. sp.

Parmal pores kidney-shaped, three or four times as large as the small circular pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines very thick, half as long in the outer conical part as in the inner cylindrical part. By-spines very short, conical.

Dimensions.—Length of the shell 0.2, breadth 0.16; length of the spines 0.05, basal breadth 0.03.

Habitat.—Central Pacific, Station 267, surface.

6. Belonaspis multiforis, n. sp.

Parmal pores circular, of the same size as the circular sutural pores. Each plate surrounded by fifteen to eighteen sutural pores (three on each side). Spines compressed, about as long as the radius. By-spines very numerous, zigzag, half as long as the radius.

Dimensions.—Length of the shell 0.22, breadth 0.18; length of the spines 0.12, basal breadth 0.012; length of the by-spines 0.06.

Habitat.—Equatorial Atlantic, Station 347, surface.

Genus 373. Dictyaspis, n. gen.

Definition.—Belonaspida with forty parmal pores (two on each plate), without by-spines, but with a network of prominent crests on the dimply surface.

The genus Dictyaspis repeats among the Belonaspida the characteristic structure of Ceriaspis (among the Dorataspida), by the development of prominent crests forming a network with dimples on the outer surface of the shields. Either all the dimples or only a part of them are pierced by a pore. The forty aspinal pores are united in pairs in twenty larger dimples. The shell is usually very thick-walled and non-transparent.

1. Dictyaspis solidissima, Haeckel.

Dorataspis solidissima, Haeckel, 1862, Monogr. d. Radiol., p. 416, Taf. xxii. figs. 6-9.

Surface of the shell with seventy to eighty funnel-shaped dimples, each of which is perforated at the base by one or two small meshes; twenty larger dimples in the centre of the plates (each with two elliptical aspinal pores), and fifty to sixty smaller sutural dimples between them (each with a single circular pore). All pores of nearly the same size. No blind dimples. Outer conical part of the thick radial spines of the same length as the inner cylindrical part. Radius of the shell four times as large as the thickness of its wall.

Dimensions.—Length of the shell 0.12, breadth 0.1; length of the spines 0.06, basal breadth 0.012.

Habitat.—Mediterranean (Messina), surface.

2. Dictyaspis favosa, n. sp.

Surface of the shell with one hundred and seventy to one hundred and ninety deep funnel-shaped dimples, seventy to eighty of which are perforated, the others blind; among the former each of the fifty to sixty smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. All pores of nearly the same size. Outer part of the compressed two-edged spines triangular, half as long as the inner part. Radius of the shell six times as large as the thickness of its wall. (Differs from Ceriaspis favosa, Pl. , fig. 6, mainly in the ellipsoidal form of the shell and the different size and form of the spines.)

Dimensions.—Length of the shell 0.16, breadth 0.13; length of the spines 0.04, basal breadth 0.025.

Habitat.—Central Pacific, Station 265, surface.

3. Dictyaspis compacta, n. sp.

Surface of the shell with one hundred and seventy to one hundred and ninety deep funnel-shaped dimples, seventy to eighty of which are perforated, the others blind; among the former each of fifty to sixty each contain a single sutural pore, twenty each a couple of aspinal pores. All dimples nearly of the same size, very deep. Outer part of the compressed sword-like spines somewhat longer than the inner part. Radius of the dark shell only twice as large as the thickness of its compact wall.

Dimensions.—Length of the shell 0.18, breadth 0.15; length of the spines 0.12, basal breadth 0.02.

Habitat.—Central Pacific, Station 274, surface.

Genus 374. Coleaspis, Haeckel, 1881, Prodromus, p. 468.

Definition.—Belonaspida with forty parmal pores (two on each plate), with numerous by-spines and with a network of prominent crests on the dimpled surface.

The genus Coleaspis differs from its ancestral genus Dictyaspis in the development of numerous by-spines, and bears therefore among the ellipsoidal Belonaspida the same relation to it as Hystrichaspis does to Coscinaspis among the spherical Dorataspida. If the four equatorial spines in Coleaspis become different in pairs, it passes over into Hexalaspis. The shell is usually very dark and thick-walled.

1. Coleaspis coronata, n. sp.

All twenty spines of nearly equal size and form, about as long as the radius of the shell, compressed, sword-like, two-edged; both equatorial spines of the hydrotomical axis little longer than the eighteen others. Crests between the dimples of the shell-surface dentated, forming around the basal half of each spine a cylindrical sheath with a dentated, crown-like mouth, the teeth of which are prolonged into simple by-spines. (Similar to Hexaconus coronatus, Pl. , fig. 5, but differing in the nearly equal size of the spines and their sheaths, and in the longer by-spines.)

Dimensions.—Major axis of the shell 0.2, minor 0.17; length of the spines 0.12, basal breadth 0.02.

Habitat.—Central Pacific, Station 266, surface.

2. Coleaspis vaginata, n. sp. (Pl. , fig. 13).

All twenty spines of nearly equal size and form, nearly as long as the diameter of the shell, conical; both equatorial spines of the hydrotomical axis about one-third longer than the eighteen others. Crests between the dimples of the shell-surface serrated, forming around the basal half of each spine a conical truncate sheath with crested surface and serrated mouth, the teeth of which are prolonged into short by-spines. (Similar to Hexaconus vaginatus, Pl. , fig. 7, but differing in the nearly equal size of all the spines and in the double thickness of the shell-wall.)

Dimensions.—Major axis of the shell 0.12, minor 0.1, length of the spines 0.08, basal breadth 0.01.

Habitat.—North Pacific, Station 253, surface.

3. Coleaspis obscura, n. sp.

All twenty spines of nearly equal size and form, little longer than their large cylindrical sheaths, which are nearly as long as the radius of the shell, and armed on the truncated mouth with strong triangular by-spines, both equatorial spines of the hydrotomical axis one and a half times as long as the eighteen others. Shell very dark and thick walled, quite opaque.

Dimensions.—Major axis of the shell 0.1, minor 0.08; length of the spines 0.06, of their sheaths 0.04.

Habitat.—Arctic Ocean, Greenland, Koch, surface.

4. Coleaspis occulta, n. sp.

All twenty spines of nearly equal size and form, quite concealed in their long cylindrical sheaths, which are somewhat longer than the radius of the shell, and armed on the truncated mouth with acute simple teeth; each sheath deeply sulcated, apparently resulting from the concrescence of numerous parallel leaf-shaped by-spines. Small shell very dark and thick-walled, quite opaque.

Dimensions.—Major axis of the shell 0.08, minor 0.06; length of the spines and their sheaths 0.05 to 0.06.

Habitat.—Antarctic Ocean (off Kerguelen), Station 159, surface.

Subgenus 2. Coleaspidium, Haeckel.

Definition.—Both equatorial spines of the hydrotomical axis much larger and of peculiar form, different from the eighteen other spines.

5. Coleaspis amphilonche, n. sp.

Both equatorial spines of the hydrotomical axis much longer than the eighteen others, and of very different form; one and a half times as long as the diameter of the shell, prismatic, with six prominent edges, pyramidal at the distal point. The eighteen other spines triangular, compressed, two-edged, scarcely as long as the radius of the thick-walled shell. Pores of the shell irregular polygonal, separated by ciliated crests, which bear simple by-spines (one-third as long as the radius).

Dimensions.—Major axis of the shell 0.15, minor 0.12; length of the two larger spines 0.22, of the eighteen smaller 0.06 to 0.08; basal breadth of the former 0.03, of the latter 0.008.

Habitat.—South Atlantic, Station 341, surface.

6. Coleaspis hydrotomica, n. sp. (Pl. , fig. 14).

Both equatorial spines of the hydrotomical axis much larger than the eighteen others, and of very different form; about as long as the diameter of the shell, in the basal half four-sided pyramidal, with four thick prominent edges, in the middle part constricted, in the distal half lanceolate, two-edged. Both equatorial spines of the geotomical axis of similar form, but much smaller, scarcely one-third as long. The sixteen other spines sword-like, thin, two-edged, about as long as the radius of the thick-walled shell. Pores of the shell irregular roundish, separated by high dentated crests, which bears zigzag by-spines (half as long as the radius).

Dimensions.—Major axis of the shell 0.12, minor axis 0.1; length of the two larger spines 0.11, of the eighteen others 0.04 to 0.06; basal breadth of the former 0.04, of the latter 0.01.

Habitat.—Cape of Good Hope, Station 143, surface.

Genus 375. Phatnaspis, Haeckel, 1881, Prodromus, p. 468

Definition.—Belonaspida with eighty to two thousand or more parmal pores (four to one hundred or more on each plate), without by-spines on the surface.

The genus Phatnaspis corresponds to the spherical Coscinaspis among the Dorataspida, and differs from the other Belonaspida in the great number of the parmal pores; whilst the four other preceding genera exhibit only two opposite aspinal pores in the centre of each plate, in this there are constantly numerous coronal pores in addition to these, and the plates always possess the characteristic form of a wainscotted or panelled work, with quadrangular meshes. The number of these parmal pores amounts in each plate to from ten to twenty, often one hundred and twenty or more; therefore the number of parmal pores in the whole shell amounts to two thousand or more. Sometimes the pores are circular, but in this case too they are surrounded by quadrangular frames. The quadrangles are sometimes quite regular squares, sometimes more or less irregular. The thin and fragile bars between the quadrangular pores form in each plate two peculiar systems of parallel crests, which cross at right angles. Commonly the parallel crests of one system (parallel to the major diameter of the compressed radial spines) are equidistant, and pierce from one edge of the plate to the opposite, whilst the parallel crests of the other system (parallel to the minor diameter of the spines) are interrupted and at different distances (Pl. , fig. 9); but in other species both crossed systems are quite regular. In each plate there is one primary diagonal rib (often stronger than the parallel crests) which connects the two opposite corners of the rhomboidal plate. We can distinguish in this genus three different subgenera: A. in Phatnasparium the primary diagonal rib arises from both flat sides of the compressed sword-like, radial spines; B. in Phatnasplenium from both sharp edges of them; C. in Phatnaspidium two crossed diagonal ribs arise from four edges of the spines (combination of A and B). Therefore in the first subgenus (A) two primary aspinal pores are placed opposite on the sharp edges of the spines, but in the second (B) inversely on their flat sides; in the third (C) there are apparently four primary aspinal pores, which are probably derived from B or A by division of the two pores.

Subgenus 1. Phatnasparium, Haeckel.

Definition.—In the centre of each rhomboidal plate two primary aspinal pores, opposite on both edges of the compressed spines, from both flat sides of which the primary diagonal crest arises.

1. Phatnaspis lacunaria, n. sp. (Pl. , fig. 9).

Parmal pores irregular quadrangular, of unequal size and form, ten to twelve on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores opposite on both edges of the latter. Spines much compressed, sword-like, their outer half shorter than the inner.

Dimensions.—Length of the shell 0.21 to 0.23, breadth 0.18 to 0.2; basal breadth of the spines 0.01.

Habitat.—Central Pacific, Station 268, surface.

2. Phatnaspis ensiformis, n. sp.

Parmal pores irregular quadrangular, of unequal size and form, six to eight on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores opposite on the two edges of the latter. Spines very broad, strongly compressed, sword-like, their outer half larger than the inner.

Dimensions.—Length of the shell 0.16, breadth 0.11; basal breadth of the spines 0.02.

Habitat.—Tropical Atlantic, Station 348, surface.

3. Phatnaspis loculata, n. sp.

Parmal pores regular quadrangular, of nearly equal size and form, twelve to sixteen on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores on the two edges of the latter. Spines linear, compressed, very long and thin, their outer half three to four times as long as the inner.

Dimensions.—Length of the shell 0.24, breadth 0.18; breadth of the spines 0.004.

Habitat.—North Atlantic, Station 354, surface.

4. Phatnaspis fenestrata, Haeckel.

Haliommatidium fenestratum, Haeckel, 1862, Monogr. d. Radiol., p. 421.

Parmal pores regular quadrangular, of nearly equal size and form, six to eight on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores on the two edges of the latter. Spines linear, little compressed, or nearly needle-shaped, very long and thin, their outer half five to ten times as long as the inner.

Dimensions.—Length of the shell 0.11 to 0.12, breadth 0.07 to 0.08; breadth of the spines 0.002.

Habitat.—Mediterranean (Messina), surface.

5. Phatnaspis cristata, n. sp. (Pl. , fig. 6).

Parmal pores circular, of very different size, separated by high square crests, ten to twelve on each side of the high, comb-like, primary diagonal rib, which arises from both flat sides of the twoedged spines; two primary aspinal pores on the two edges of the latter. Each circular pore is surrounded by a square frame. Spines sword-like, strongly compressed, their outer part longer than the inner.

Dimensions.—Length of the shell 0.2 to 0.22, breadth 0.16 to 0.18; basal breadth of the spines 0.01.

Habitat.—North Pacific, Station 254, surface.

6. Phatnaspis coscinoides, n. sp.

Parmal pores circular, regular, all of nearly equal size, twelve to sixteen on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary pores on the two edges of the latter. Spines linear, little compressed, their outer part much longer than the inner.

Dimensions.—Length of the shell 0.18, breadth 0.15; breadth of the spines 0.006.

Habitat.—South Atlantic, Station 325, surface.

Subgenus 2. Phatnasplenium, Haeckel.

Definition.—In the centre of each rhomboidal plate two primary aspinal pores, opposite on the two flat sides of the compressed spines, from the two edges of which the primary diagonal crest arises.

7. Phatnaspis orthopora, n. sp.

Parmal pores irregular quadrangular, of unequal size and form, four to six on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two larger primary aspinal pores opposite on the two flat sides of the latter. Spines very thin and long, linear, their outer half three to four times as long as the inner.

Dimensions.—Length of the shell 0.08, breadth 0.06; breadth of the spines 0.003.

Habitat.—North Atlantic, Station 353, surface.

8. Phatnaspis polypora, n. sp.

Parmal pores irregular polygonal, of very unequal size and form, sixteen to twenty on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two very large, lanceolate, primary aspinal pores opposite on the two flat sides of the latter. Spines very thin, linear, on the outside of the shell rudimentary. (This remarkable species somewhat resembles Coscinaspis polypora, Pl. , fig. 8.)

Dimensions.—Length of the shell 0.32, breadth 0.24; breadth of the spines 0.002.

Habitat.—South Atlantic, Station 332, surface.

9. Phatnaspis quadratura, n. sp.

Parmal pores regular, square, all of nearly equal size and form, ten to twelve on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two primary aspinal pores opposite on the two flat sides of the latter, not different from the other pores. Spines sword-like, their outer part about as long as the inner.

Dimensions.—Length of the shell 0.2, breadth 0.16; basal breadth of the spines 0.004.

Habitat.—Central Pacific, Station 274, surface.

10. Phatnaspis tabulata, Haeckel.

Haliomma tabulatum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 37, Taf. v. figs. 5-8.

Haliomma tabulatum, Haeckel, 1862, Monogr. d. Radiol., p. 429.

Parmal pores regular, circular, with square frames, all of nearly equal size, eight to ten on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two primary aspinal pores opposite on the flat sides of the latter. Spines sword-like, short, scarcely half as long as the radius of the shell, their central ends are thickened and cause by their union the deceptive appearance of an enclosed "medullary shell."

Dimensions.—Length of the shell 0.12 to 0.15, breadth 0.1 to 0.12; breadth of the spines 0.006.

Habitat.—Mediterranean; Nice, Müller; Portofino, near Genoa, Haeckel, surface.

Subgenus 3. Phatnaspidium, Haeckel.

Definition.—In the centre of each rhomboidal plate four primary aspinal spines, forming a regular cross, the centre of which receives the cylindrical or four-sided prismatic spine.

11. Phatnaspis haliommidium, n. sp. (Pl. , fig. 7).

Parmal pores irregular quadrangular, of unequal size and form, eight to ten on each side of the crossed diagonal ribs, which arise at right angles from the four edges of the prismatic spines; four primary aspinal pores not different from the others. Outer part of the strong spines scarcely longer than the inner. (Resembling Icosaspis tabulata, Pl. , fig. 2, which, however, is distinguished by the spherical shell and the larger pores.)

Dimensions.—Length of the shell 0.22, breadth 0.17; breadth of the spines 0.016.

Habitat.—North Pacific, Station 244, surface.

12. Phatnaspis mülleri, n. sp.

Haliommatidium mülleri, Haeckel, 1862, Monogr. A. Radiol, p. 419, pl. xiii. figs. 10-12.

Parmal pores regular, square, all of nearly equal size and form, twelve to sixteen on each side of the crossed diagonal ribs, which arise at right angles from the needle-shaped spines; the four primary aspinal pores not different from the others. Spines very thin and long, cylindrical; four to six times longer in the outer than in the inner part.

Dimensions.—Length of the shell 0.24, breadth 0.16; breadth of the spines 0.002.

Habitat.—Mediterranean (Messina), surface.