2. Quadrilonche platystaura, n. sp. (Pl. 131, fig. 2).
Four equatorial spines lanceolate, compressed, with two opposite triangular simple apophyses in the broadest middle part. Sixteen other spines also lanceolate, much smaller, of about half the length, but only of one-fourth the breadth, without apophyses.
Dimensions.—Length of the four major spines 0.2, breadth 0.018; length of the sixteen minor spines 0.1, breadth 0.004.
Habitat.—North Pacific, Station 235, surface.
Definition.—All twenty spines provided with transverse apophyses.
3. Quadrilonche mesostaura, n. sp. (Pl. 131, fig. 1).
Four equatorial spines almost of the some form and length as the sixteen others, but of double or triple the breadth; each spine in its middle third with two opposite broad triangular apophyses, in the basal third rectangular, compressed, in the distal third isosceles triangular, with simple apex.
Dimensions.—Length of the four major spines 0.16, breadth 0.01 to 0.015; length of the sixteen minor spines 0.12, breadth 0.005.
Habitat.—Tropical Atlantic, Station 345, surface.
4. Quadrilonche telostaura, n. sp.
Four equatorial spines one and a half times as long and three times as broad as the sixteen others; all twenty spines cylindrical, of equal breadth throughout their whole length, with simple conical apex; each spine crossed in the distal third by two opposite, simple, conical apophyses.
Dimensions.—Length of the four major spines 0.3, breadth 0.012; length of the sixteen minor spines 0.2, breadth 0.004.
Habitat.—South Atlantic, Station 325, surface.
Definition.—Quadrilonchida with two opposite branched (but not latticed) apophyses, either on each radial spine or only on a part of the twenty spines.
The genus Xiphoptera differs from the preceding ancestral genus Quadrilonche in the ramification of the apophyses, which bear perpendicular branches on their distal side. These are therefore parallel to the spine itself. If the branches become united by transverse beams then we get Lithoptera.
1. Xiphoptera tessaractena, n. sp.
Four equatorial spines in the outer third crossed by two opposite transverse apophyses, each of which bears on its distal side two to three branches, perpendicular to the apophysis and parallel to the spine itself. Sixteen other spines much smaller, in the outer third crossed by two simple opposite transverse apophyses.
Dimensions.—Length of the four major spines 0.18, of the sixteen minor 0.05 to 0.1.
Habitat.—North Pacific, Station 238, surface.
2. Xiphoptera dodecactena, n. sp. (Pl. 131, fig. 3).
Four equatorial spines one and a half times to twice as long and broad as the eight tropical spines. These twelve spines have the same form and are crossed in their distal third by two large opposite transverse apophyses, each of which bears on its distal side two to four branches, perpendicular to the apophysis and parallel to the spine. Eight polar spines much smaller than the twelve others, simple, without apophyses. The central capsule of this species exhibited a conical protuberance around the base of each individual spine.
Dimensions.—Length of the twelve larger spines 0.1 to 0.2, of the eight smaller 0.02 to 0.06.
Habitat.—Central Pacific, Station 272, surface.
3. Xiphoptera icosactena, n. sp.
Four equatorial spines about twice as long and four times as broad as the sixteen other spines. All twenty spines crossed in the outer third by two large opposite transverse apophyses, each of which bears on its distal side two to four branches perpendicular to the apophysis and parallel to the spine itself.
Dimensions.—Length of the four equatorial spines 0.26, of the sixteen smaller 0.11 to 0.14.
Habitat.—South Pacific, Station 288, surface.
Definition.—Quadrilonchida with two opposite branched and latticed apophyses, either on each radial spine or only on a part of the twenty spines.
The genus Lithoptera, founded by Johannes Müller in 1858 for the first observed Mediterranean species, Lithoptera fenestrata, differs from all other Quadrilonchida in the fenestrated form of the apophyses, which he compared to the sails of a windmill. This peculiar fenestration is effected by two to four parallel pairs of opposite apophyses, which are crossed by perpendicular branches, parallel to the spine itself. Therefore the wings or lattice-plates have quadrangular meshes and lie in one meridian plane of the spine, not in a tangential plane (as in the Acanthophracta). Commonly the lateral ends of the four broad equatorial wings are so crossed that one lateral corner of each wing lies on the upper, the other corner on the under side of both its neighbours; but sometimes the meeting corners have grown together.
Definition.—Four equatorial spines with transverse apophyses; sixteen others (eight tropical and eight polar spines) simple, without apophyses.
1. Lithoptera tetraptera, n. sp. (Pl. 131, fig. 9).
Four equatorial spines spindle-shaped, with latticed apophyses, each crossed by two transverse beams which are connected at equal distances by four rods parallel to the spine (therefore each wing with four square meshes in a single row). Lateral corners of the neighbouring wings not meeting. Sixteen smaller spines (eight tropical and eight polar) simple, conical, without apophyses.
Dimensions.—Diagonal of the square body 0.24; length of the inner square 0.16.
Habitat.—Tropical Atlantic, Station 348, surface.
2. Lithoptera mülleri, Haeckel.
Lithoptera mülleri, Haeckel, 1862, Monogr. d. Radiol., p. 398, Taf. xx. figs. 1, 2.
Four equatorial spines four-edged, with large latticed apophyses, each crossed by three transverse beams, which are connected at irregular distances by eight to twelve rods parallel to the spine (therefore each wing with two rows of rectangular meshes). The wings are placed not perfectly in the equatorial plane, but a little obliquely, so that each wing lies with one lateral corner on the upper, with the other corner on the under side of its neighbours. Sixteen smaller spines simple, thin, cylindrical, without apophyses.
Dimensions.—Diagonal of the square body 0.3; length of the inner square 0.17.
Habitat.—Mediterranean (Messina), surface.
3. Lithoptera lamarckii, n. sp.
Four equatorial spines four-edged, with large latticed apophyses; each crossed by three transverse beams, which are connected at short distances by twelve to sixteen rods parallel to the spine (therefore each wing with two rows of hexagonal or nearly elliptical meshes). Wings placed as in Lithoptera mülleri. Sixteen smaller spines simple, thin, prismatic, without apophyses.
Dimensions.—Diagonal of the square body 0.35; length of the inner square 0.2.
Habitat.—Central Pacific, Station 271, surface.
4. Lithoptera tetragona, n. sp.
Four equatorial spines compressed, four-edged, with large latticed apophyses, each crossed by four transverse beams, which are connected at regular distances by eight to twelve rods parallel to the spine. (Therefore each wing with three rows of square meshes.) Wings placed in the equatorial plane and grown together by their meeting lateral ends, forming a square equatorial girdle of lattice-work. Sixteen smaller spines simple, thin, prismatic, without apophyses.
Dimensions.—Diameter of the square body 0.4; length of the inner square 0.22.
Habitat.—North Pacific, Station 244, surface.
Definition.—Twelve spines (four equatorial and eight tropical) with transverse apophyses; the eight polar spines simple, without apophyses.
5. Lithoptera quadrata, n. sp. (Pl. 131, fig. 10).
Twelve spines with transverse apophyses; eight (polar) spines simple, small, without apophyses. Four equatorial spines very large and stout, compressed, each crossed by four transverse beams, which are connected by eight to ten rods parallel to the spine (therefore each wing with three rows of irregular rectangular meshes). Wings placed in the equatorial plane and grown together by their meeting lateral ends, forming a square equatorial girdle of lattice-work. Eight tropical spines thin, crossed by a long and thin transverse beam, which bears on its distal side eight to ten rods parallel to the spine.
Dimensions.—Diagonal of the square body 0.35; length of the inner square 0.18.
Habitat.—South Atlantic, Station 326, surface.
6. Lithoptera dodecaptera, n. sp.
Twelve spines with transverse apophyses; eight (polar) spines simple, small, without apophyses. Four equatorial spines very large, quadrangular; each crossed by three transverse beams, which are connected by ten to twelve rods parallel to the spine (therefore each wing with two rows of square meshes). Wings placed as in Lithoptera mülleri. Eight tropical spines much thinner, crossed each by two transverse beams, which are connected by six to eight rods parallel to the spine (therefore each wing with one row of rectangular meshes).
Dimensions.—Diagonal of the square body 0.4; length of the inner square 0.25.
Habitat.—Central Pacific, Station 271, surface.
Definition.—All twenty spines with transverse apophyses.
7. Lithoptera darwinii, Haeckel.
Lithoptera darwinii, Haeckel, 1879, Natürl. Schöpfungsgesch., Aufl. vii. p. 706, Taf. xvi. fig. 12.
All twenty spines with transverse apophyses; these are quite simple in the eight small cross-shaped polar spines; also simple, but bearing some perpendicular rods, in the eight thin tropical spines. Four equatorial spines very large and stout, each crossed by four transverse beams, which are connected by eight to ten rods parallel to the spine (therefore each wing with three rows of irregular rectangular meshes). Wings placed in the equatorial plane and grown partly together by their meeting lateral ends.
Dimensions.—Diagonal of the square body 0.4; length of the inner square 0.2.
Habitat.—South-east Pacific, west coast of Patagonia, Station 302, surface.
8. Lithoptera icosaptera, n. sp.
All twenty spines with transverse apophyses, bearing one to three rows of rectangular meshes; eight polar spines small, each with a single row; eight tropical spines long and thin, each with two parallel rows. Four equatorial spines much larger and thicker, each with three parallel transverse rows of meshes. All twenty wings free, not grown together by their lateral ends.
Dimensions.—Diagonal of the square body 0.48; length of the inner square 0.24.
Habitat.—Indian Ocean, Belligemma, Ceylon (Haeckel), surface.
9. Lithoptera fenestrata, J. Müller.
Lithoptera fenestrata, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 154, Taf. xi. fig. 13.
All twenty spines with transverse apophyses, bearing one to three rows of irregular, rectangular meshes; eight polar and eight tropical spines small, each with a single row of meshes (between two parallel transverse beams). Four equatorial spines little larger, each with two rows (between three parallel transverse beams). Central capsule filled up with green pigment.
Dimensions.—Diagonal of the square body 0.3; length of the inner square 0.2.
Habitat.—Mediterranean (Saint Tropez, Nice).
Acantholonchida (Amphilonchida et Amphilithida), Haeckel, 1881, Prodromus, p. 466.
Definition.—Acantharia with twenty radial spines of very unequal size, disposed according to the law of the Icosacantha; two opposite equatorial spines (in the longitudinal axis) much larger than the eighteen others. No lattice-shell.
The family Amphilonchida is distinguished from all other Acanthometra by the excessive development of two opposite equatorial spines, which are much larger than the eighteen other spines. In my Monograph (1862, p. 389) I had united all these Acanthonida in a single genus Amphilonche (with ten species). Some species of it are very common and widely distributed; but in general the number of different forms in this family is much smaller than in the two foregoing families.
The two principal spines, which in all Amphilonchida are much larger than the eighteen other spines, characterise the "hydrotomical axis" or the larger equatorial axis. The two other equatorial spines or the "geotomical spines" are much smaller, and commonly of the same size as the eight tropical and the eight polar spines. In the genera Amphilonche and Amphibelone these eighteen smaller spines are rather equally developed; sometimes they are very small or quite rudimentary, so that the skeleton seems to be represented only by the two very long principal spines (Pl. 132, fig. 4). The genus Acantholonche is distinguished by the unequal size of the eight tropical and the eight polar spines, the latter being more or less rudimentary. However, the central bases of all twenty spines, by which they are united in the centre, are constantly present. The genus Amphibelone is distinguished by the unequal size and form of the two principal spines, one of them the "caudal spine," being larger (and often of another form) than the opposite "frontal spine."
The form of the radial spines is in the Amphilonchida far less varied and complicated than in the other Acanthonida (the Astrolonchida and Quadrilonchida). Apophyses or lateral transverse processes are never developed. The three main forms of spines are the same as in the other Acanthonida; they are (1) either cylindrical or conical (like Acanthometron), or (2) compressed or two-edged (like Zygacantha), or (3) quadrangular or four-edged (like Acanthonia). Often the spines are angular in the inner or proximal, roundish in the outer or distal part. The distal apex is commonly simple, conical or pyramidal. The central base is commonly also pyramidal, as in the majority of the Acanthonida; and the triangular faces of the neighbouring bases are simply propped one upon another. More rarely a basal leaf-cross is developed above the basal pyramid. Very rarely the central bases of the united spines grow together in the centre, so that the whole skeleton forms a single piece of acanthin.
The Central Capsule is rarely spherical, commonly prolonged in the direction of the hydrotomical axis; ellipsoidal or cylindrical, sometimes also four-sided prismatic; it commonly envelops the greater part of the two principal spines; its structure and contents are the same as in the other Acanthonida.
| Eighteen smaller spines of nearly equal size and similar form. | brace | Two opposite large principal spines (frontal and caudal) equal, | 341. Amphilonche. |
| Caudal spine larger than the frontal spine, | 342. Amphibelone. | ||
| Eight tropical and eight polar spines of different sizes (the latter often rudimentary), | 343. Acantholonche. | ||
| Eighteen smaller spines of nearly equal size and similar form. | ||||
| Two opposite large principal spines (frontal and caudal) equal, | ||||
| 341. Amphilonche. | ||||
| Caudal spine larger than the frontal spine, | ||||
| 342. Amphibelone. | ||||
| Eight tropical and eight polar spines of different sizes (the latter often rudimentary), | ||||
| 343. Acantholonche. | ||||
Definition.—Amphilonchida with two equal principal spines (frontal and caudal spines not different); the eighteen smaller spines nearly equal.
The genus Amphilonche represents the original and at the same time the most common form of Amphilonchida; the two opposite principal spines are of equal size and form, much larger (and often also of another form) than the eighteen smaller spines; these latter exhibit no marked differences in size and form.
Definition.—Spines in the centre united by triangular faces of their pyramidal bases, propped one upon another. No basal leaf-cross.
1. Amphilonche belonoides, Haeckel.
Amphilonche belonoides, Haeckel, 1862, Monogr. d. Radiol., p. 392, Taf. xvi. fig. 6, Taf. xviii. fig. 21.
Acanthometra belonoides, Haeckel, 1860, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 808.
Two principal spines cylindrical, of equal breadth throughout their whole length, with simple conical apex; base a small pyramid, without leaf-cross. Eighteen smaller spines conical, much shorter, with simple bristle-shaped apex. Central capsule spindle-shaped or cylindrical, yellow.
Dimensions.—Length of the two major spines 0.4 to 0.8, of the eighteen minor 0.05 to 0.2.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.
2. Amphilonche lanceolata, n. sp. (Pl. 132, fig. 1).
Two principal spines compressed, lanceolate, two-edged, gradually tapering from the broader middle towards the two ends; apex simple; base a large pyramid, with broad leaf-cross. Eighteen smaller spines about half as long, pyramidal, with simple conical or bristle-shaped apex. Central capsule lentelliptical, pink, opaque.
Dimensions.—Length of the two major spines 0.2, of the eighteen minor 0.1.
Habitat.—Tropical Atlantic, Station 343, surface.
3. Amphilonche diodon, n. sp. (Pl. 132, fig. 3).
Two principal spines compressed, lanceolate, two-edged, tapering from the broader middle towards the two ends; apex simple; base a small pyramid, without leaf-cross. Eighteen smaller spines sword-shaped, only two-thirds or one-half as long, and one-third or one-fourth as broad, each with two opposite teeth in the distal part. Central capsule ellipsoidal.
Dimensions.—Length of the two major spines 0.13, breadth 0.02; length of the eighteen minor spines 0.1.
Habitat.—North Atlantic, Station 352, surface.
4. Amphilonche tenuis, Haeckel.
Amphilonche tenuis, Haeckel, 1862, Monogr. d. Radiol., p. 389, Taf. xvi. fig. 1, Taf. xviii. fig. 16.
Acanthometra tenuis, Haeckel, 1860, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 807.
Two principal spines quadrangular prismatic, with smooth edges, slightly or not at all prominent, of equal breadth throughout their whole length; apex simple or bifid; base a small pyramid, without leaf-cross. Eighteen smaller spines of the same form, but only one-fourth or one-third as long. Central capsule spherical or ellipsoidal, colourless.
Dimensions.—Length of the two major spines 0.2 to 0.3, of the eighteen minor spines 0.05 to 0.1.
Habitat.—Mediterranean (Messina); Atlantic, Station 354, Canary Islands, surface.
5. Amphilonche denticulata, Haeckel.
Amphilonche denticulata, Haeckel, 1862, Monogr. d. Radiol., p. 390, Taf. xvi. fig. 2, Taf. xviii. fig. 17.
Two principal spines quadrangular prismatic, with prominent, elegantly denticulated edges, of equal breadth throughout their whole length; apex simple or truncated; base a small pyramid, without leaf-cross. Eighteen smaller spines of the same form, but only one-fourth or one-third as long. Central capsule ellipsoidal, opaque, yellowish-brown.
Dimensions.—Length of the two major spines 0.3 to 0.4, of the eighteen minor 0.1; breadth of the former 0.009, of the latter 0.006.
Habitat.—Mediterranean (Messina), Haeckel, surface.
6. Amphilonche heteracantha, Haeckel.
Amphilonche heteracantha, Haeckel, 1862, Monogr. d. Radiol., p. 293, Taf. xvi. fig. 7.
Acanthometra heteracantha, Haeckel, 1860, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 808.
Two principal spines quadrangular prismatic, very large, with four broad, prominent, lamellar edges, of equal breadth throughout their whole length. Apex as well as the base a four-sided pyramid. Eighteen smaller spines very thin, conical, with bristle-shaped apex; base a small pyramid, without leaf-cross. Central capsule cylindrical or violin-shaped, opaque yellow.
Dimensions.—Length of the two major spines 0.2 to 0.3, breadth 0.015 to 0.02; length of the eighteen minor spines 0.1 to 0.15, basal breadth 0.004 to 0.008.
Habitat.—Mediterranean (Messina); Central Pacific, Station 271, surface.
7. Amphilonche elongata, Haeckel.
Amphilonche elongata, Haeckel, 1862, Monogr. d. Radiol., p. 392, Taf. xviii. figs. 22a, 22b.
Acanthometra elongata, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 48, Taf. vii. fig. 13.
Two principal spines quadrangular prismatic in the proximal half, cylindrical or spindle-shaped in the distal half, with simple apex; base a small pyramid, without leaf-cross. Eighteen smaller spines very thin, bristle-shaped, conical on the base, with small pyramid. Central capsule spindle-shaped, transparent, yellow.
Dimensions.—Length of the two major spines 0.3 to 0.5, breadth 0.01 to 0.03; length of the eighteen smaller spines 0.05 to 0.3.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.
Definition.—Spines at the central base with a broad leaf-cross, composed of four prominent triangular lamellæ; between the meeting edges of the latter twenty-two pyramidal compartments or basal funnels.
8. Amphilonche ovata, Haeckel.
Amphilonche ovata, Haeckel, 1862, Monogr. d. Radiol., p. 390.
Acanthometra ovata, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 47, Taf. vii. fig. 10, Taf. ix. fig. 4.
Two principal spines cylindrical, of equal breadth throughout their whole length, with simple conical or bifid apex; base with a large leaf-cross of double the breadth. Eighteen smaller spines of the same form, but thinner and only half as long. Central capsule ellipsoidal, brown, opaque.
Dimensions.—Length of the two major spines 0.3 to 0.4, breadth 0.008 to 0.012; length of the eighteen minor spines 0.1 to 0.2.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.
9. Amphilonche conica, n. sp. (Pl. 132, fig. 6).
Two principal spines conical, elongate, with simple apex; base thickened, with large leaf-cross. Eighteen smaller spines also conical, of about the same basal breadth, but only one-fourth to one-half as long. Central capsule ellipsoidal, pellucid.
Dimensions.—Length of the two major spines 0.15 to 0.2, basal breadth 0.03 to 0.04; length of the eighteen minor spines 0.05 to 0.1.
Habitat.—Central Pacific, Stations 265 to 274, surface.
10. Amphilonche lancetta, n. sp.
Two principal spines compressed, lanceolate, two edged, gradually tapering from the broader middle towards the two ends; apex simple; base of double the breadth, with a large leaf-cross. Eighteen smaller spines of the same form, but shorter and only half as broad. Central capsule lentelliptical, pellucid.
Dimensions.—Length of the two major spines 0.2 to 0.3, breadth in the middle part 0.02 to 0.03; length of the eighteen smaller spines 0.1 to 0.2.
Habitat.—South Pacific, Station 288, surface.
11. Amphilonche complanata, Haeckel.
Amphilonche complanata, Haeckel, 1862, Monogr. d. Radiol., p. 390, Taf. xvi. fig. 3, Taf. xviii. fig. 18, a, b.
Acanthometra complanata, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 808.
Two principal spines compressed, two-edged, linear, of equal breadth throughout their whole length; apex emarginate or bifid; base with a large leaf-cross of double the breadth. Eighteen smaller spines of the same form, but only one-fourth to one-half as large. Central capsule ellipsoidal, yellow, pellucid.
Dimensions.—Length of the two major spines 0.15 to 0.25, breadth 0.004 to 0.006; length of the eighteen minor spines 0.05 to 0.1.
Habitat.—Mediterranean (Messina), surface.
12. Amphilonche messanensis, Haeckel.
Amphilonche messanensis, Haeckel, 1862, Monogr. d. Radiol., p. 391, Taf. xvi. fig. 4, Taf. xviii. fig. 19.
Acanthometra messanensis, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 808.
Two principal spines quadrangular prismatic, often a little compressed from two sides, of nearly equal breadth throughout their whole length; apex either truncate or emarginate, with two opposite teeth; base with a large leaf-cross of double the breadth. Eighteen smaller spines of similar form or more compressed, much shorter. Central capsule spherical or ellipsoidal, yellow, transparent.
Dimensions.—Length of the two major spines 0.12 to 0.18, breadth 0.016; length of the minor spines 0.05 to 0.09.
Habitat.—Mediterranean (Messina, Corfu), Haeckel, surface.
13. Amphilonche hydrotomica, n. sp. (Pl. 132, fig. 2).
Two principal spines quadrangular prismatic, with four broad prominent lamellar edges or wings, of equal breadth throughout their whole length; apex pyramidal; base with a large leaf-cross. Eighteen smaller spines cylindrical or bristle-shaped, only half as long and very thin. Central capsule cylindrical or spindle-shaped, very long, opaque.
Dimensions.—Length of the two major spines 0.1 to 0.2, breadth 0.02 to 0.03; length of the eighteen minor spines 0.05 to 0.1.
Habitat.—Central Pacific, Stations 270 to 274, surface.
14. Amphilonche violina, n. sp. (Pl. 132, fig. 5).
Two principal spines quadrangular prismatic, nearly violin-shaped, with four very broad, prominent, lamellar wings, which are constricted in the middle part, and broadened towards the two ends; apex truncate pyramidal; base with a large leaf-cross. Eighteen smaller spines much shorter, of equal breadth at the base, assuming the form of a quadrangular pyramid, thin prismatic in the distal half. Central capsule spindle-shaped, opaque.
Dimensions.—Length of the two major spines 0.15 to 0.18, breadth 0.02 to 0.025; length of the eighteen minor spines 0.04 to 0.08.
Habitat.—Central Pacific, Station 271, surface.
15. Amphilonche tetraptera, Haeckel.
Amphilonche tetraptera, Haeckel, 1862, Monogr. d. Radiol., p. 391, Taf. xvi. fig. 5, Taf. xviii. fig. 20.
Acanthometra tetraptera, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 808.
Two principal spines four-sided pyramidal, with four broad lamellar prominent edges; apex simple or bifid; base with a large leaf-cross. Eighteen smaller spines of similar form, but only half as large. Central capsule spherical, opaque.
Dimensions.—Length of the two major spines 0.2, breadth on the base 0.025; length of the eighteen minor spines 0.1.
Habitat.—Mediterranean (Messina); North Atlantic, Canary Islands, Stations 352 to 354, surface.
Definition.—Spines in the basal part grown together, so that the whole skeleton represents a single piece of acanthin; a star with two larger and eighteen smaller rays.
16. Amphilonche concreta, n. sp. (Pl. 132, figs. 4, 4a).
Two principal spines cylindrical, very long, of equal breadth throughout their whole length, with simple conical apex. Eighteen smaller spines short, conical or bristle-shaped, scarcely one-fourth or one-tenth as long, often quite rudimentary. All twenty spines perfectly grown together in the centre, forming a single piece of acanthin (derived from Amphilonche belonoides by central concrescence; often the sutures of the concreted bases are visible, fig. 4a).
Dimensions.—Length of the two major spines 0.1 to 0.4, breadth 0.005 to 0.015; length of the eighteen minor spines 0.005 to 0.15.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.
17. Amphilonche acufera, n. sp.
Two principal spines thick, four-sided prismatic in the basal half, cylindrical or spindle-shaped in the distal half, with simple conical apex. Eighteen smaller spines shorter, thin, bristle-shaped or conical on the base. All twenty spines in the centre perfectly grown together, forming a single piece of acanthin. (Derived from Amphilonche elongata by central concrescence.)
Dimensions.—Length of the two major spines 0.3 to 0.5, breadth 0.01 to 0.03; length of the eighteen minor spines 0.08 to 0.2.
Habitat.—Central Pacific, Stations 266 to 274, surface.
Definition.—Amphilonchida with two unequal principal spines (the frontal spine very different from the caudal spine); the eighteen smaller spines nearly equal.
The genus Amphibelone exhibits among the Amphilonchida the same remarkable differentiation of the two principal or longitudinal spines, as Zygostaurus among the Quadrilonchida; the frontal spine differs commonly from the caudal spine not only in its size, but also in its peculiar form; commonly one pole of the longitudinal axis is much more strongly developed than the other. The eighteen smaller spines are nearly equal.
Definition.—All twenty spines separate, but in contact in the centre and resting one against another by the triangular sides of their pyramidal bases, without a prominent basal leaf-cross.
1. Amphibelone aciculata, n. sp.
Two principal spines thick, without edges and wings, the frontal spine short, spindle-shaped, the caudal three to six times as long, cylindrical, both of equal breadth, with simple conical apex and simple pyramidal base, without leaf-cross. Eighteen smaller spines very thin, bristle-shaped, of the same length as the frontal spine. Central capsule cylindrical or spindle-shaped, enveloping the two principal spines nearly throughout their whole length.
Dimensions.—Length of the frontal spine 0.2 to 0.4, of the caudal spine 1.0 to 2.0; breadth of both 0.01; length of the eighteen smaller spines 0.1 to 0.3.
Habitat.—South Atlantic, Station 325, surface.
2. Amphibelone cultellata, n. sp. (Pl. 132, fig. 10).
Two principal spines broad, two-edged, knife-shaped; two opposite in the equatorial plane, thin and broad wings or lamellæ are developed, and these enclose the proximal part of both spines, whilst their distal part is free, cylindrical, with conical apex: the two wings of the longer caudal spine are lanceolate, twice to four times as broad as the two wings of the shorter frontal spine; their base is a simple pyramid without leaf-cross. Eighteen smaller spines conical, with bristle-shaped prolongation, one-fourth to one-half as long as the frontal spine. Central capsule green, semitransparent.
Dimensions.—Length of the frontal spine 0.1 to 0.2, breadth 0.02 to 0.03; length of the caudal spine 0.2 to 0.4, breadth 0.04 to 0.08; length of the eighteen smaller spines 0.05 to 0.15.
Habitat.—Indian Ocean, Maldive Islands (Haeckel), surface.
3. Amphibelone pyramidata, n. sp. (Pl. 132, fig. 9).
Two principal spines four-winged, with four crossed, very thin and broad wings, which are somewhat broader in the convex middle part than at either end; both ends of each spine four-sided pyramidal, with four concave edges and a very small terminal pyramid; base without leaf-cross. The longer caudal spine is twice as broad at the distal end as at its proximal end, and three times as broad as the distal end of the shorter frontal spine. Eighteen smaller spines bristle-shaped, with four-sided pyramidal bases. Central capsule pyramidal, enveloping the two principal spines throughout their whole length; the base of the slender quadrangular pyramid is on the caudal, the apex on the frontal pole of the longitudinal axis.
Dimensions.—Length of the frontal spine 0.2 to 0.25, distal breadth 0.01; length of the caudal spine 0.3 to 0.4, distal breadth 0.03; length of the eighteen smaller spines 0.04 to 0.08.
Habitat.—Cape of Good Hope, Station 143, depth 1900 fathoms.
4. Amphibelone anomala, Haeckel.
Amphilonche anomala, Haeckel, 1862, Monogr. d. Radiol., p. 394, Taf. xvi. fig. 8, Taf. xviii. figs. 23a, 23b.
Acanthometra anomala, Haeckel, 1860, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 808.
Two principal spines four-winged, nearly prismatic, with four crossed, very broad and thick wings; both ends of each spine four-sided pyramidal, with four concave edges and a very small terminal pyramid; base without leaf-cross. The edges of the four wings are concave on the shorter frontal, convex on the longer caudal spine. Eighteen smaller spines only one-fourth to one-half as long, linear, two-edged, with two parallel teeth on the distal end. Central capsule four-sided prismatic, olive-green, enveloping almost completely the two principal spines.
Dimensions.—Length of the frontal spine 0.12, middle breadth 0.016; length of the caudal spine 0.14, middle breadth 0.024; length of the eighteen smaller spines 0.04 to 0.06.
Habitat.—Mediterranean (Messina), surface.
Definition.—All twenty spines grown together in the centre, forming a single star-shaped piece of acanthin.
5. Amphibelone clavaria, n. sp.
Two principal spines roundish, without edges and wings; the smaller frontal spine elongate conical, the larger caudal spine two to four times as long, cylindrical, in the distal part spindle-shaped or club-shaped, with conical apex. Central base simple pyramidal, without leaf-cross. Eighteen smaller spines much shorter, bristle-shaped. Central capsule very long, club-shaped. All twenty spines perfectly grown together in the centre.
Dimensions.—Length of the frontal spine 0.12, of the caudal spine 0.4 to 0.8; frontal breadth 0.01, caudal breadth 0.03; length of the eighteen smaller spines 0.05.
Habitat.—Central Pacific, Station 272, surface.
Definition.—Amphilonchida with two equal principal spines (frontal and caudal spines not different). The eighteen smaller spines are very unequal, ten of them (eight tropical and two transverse equatorial spines) much larger than the rudimentary eight polar spines.
The genus Acantholonche differs from its ancestral genus Amphilonche in the different shape of the eight tropical and the eight polar spines; these latter are much smaller than the former, which are almost equal to the two transverse equatorial spines. The two principal spines are equal, but in size and shape very different from the others.
1. Acantholonche amphipolaris, n. sp. (Pl. 132, fig. 7).
Two principal spines stout, quadrangular prismatic in the basal half, cylindrical or spindle-shaped in the distal half, with simple conical apex; base a small pyramid without leaf-cross. Two transverse and eight tropical spines, about half as long as the former, very thin, bristle-shaped, conical at the basal part. Eight polar spines very small, scarcely one-eighth or one-fourth as long as the latter, short pyramidal or conical, often quite rudimentary. Central capsule cylindrical, enveloping the basal half of the two principal spines.
Dimensions.—Length of the two principal spines 0.4 to 0.5, of the ten smaller spines 0.2 to 0.3, of the eight rudimentary polar spines 0.01 to 0.06; breadth of the two large spines 0.02 to 0.03.
Habitat.—Central Pacific, Stations 266 to 274, surface.