Page:Scientific results HMS Challenger vol 18 part 1.djvu/991

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Definition.— 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