Page:Scientific results HMS Challenger vol 18 part 2.djvu/346

1222 3. Eucecryphalus cuvieri, n. sp.

Shell flatly conical, with slight collar stricture. Length of the two joints = 1 : 8, breadth = 2 : 10. Cephalis hemispherical, with an oblique pyramidal horn twice as long. Thorax with straight outlines and regular hexagonal meshes, increasing in size towards the mouth. From the collar stricture there arise three stout conical spines, half as long as the thorax, and diverging downwards. Peristome with a ring of small square pores and alternate conical divergent spines. Differs from the similar Clathrocyclas alcmenæ (Pl. 59, fig. 6), mainly in the simple apical horn and the possession of the three collar fundamental spines.

Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.15 long, 0.2 broad.

Habitat.—Tropical Atlantic, Station 342, depth 1445 fathoms.

4. Eucecryphalus mülleri, n. sp.

Shell flatly campanulate, of nearly the same structure as and similar form to that of the preceding species. Differs from it mainly in the considerable size of the cephalic horn and the three collar spines, which are bristle-shaped and longer than the shell. Length of the two joints = 1 : 4, breadth = 2 : 8. The peristome bears a double marginal ring of divergent conical spines, the upper being directed upwards, the lower downwards.

Dimensions.—Cephalis 0.02 long, 0.04 broad; thorax 0.08 long, 0.16 broad.

Habitat.—North Pacific, Station 241, depth 2300 fathoms.

5. Eucecryphalus gegenbauri, Haeckel.

Eucecryphalus gegenbauri, Haeckel, 1862, Monogr. d. Radiol., p. 308, Taf. v. figs. 12-15.

Eucecryphalus gegenbauri, R. Hertwig, 1879, Organism. d. Radiol., p. 76, Taf. viii. figs. 5, 5a, 5b.

Shell flatly conical, campanulate, with slight collar stricture. Length of the two joints = 1 : 4, breadth = 1 : 8. Cephalis hemispherical, with a conical horn of the same length, and very small pores. Thorax about twice as broad as high, with large, subregular, hexagonal meshes, increasing in size downwards. In the upper half of the thorax the meshes are filled up by an extremely delicate arachnoidal network. From the collar stricture there arise three divergent bristle-shaped spines half as long as the thorax. Peristome with a double coronal of small square pores (the inner smaller and more numerous than the outer), and with a single coronal of divergent marginal spines. This cosmopolitan species is rather variable.

Dimensions.—Cephalis 0.02 to 0.03 diameter; thorax 0.1 to 0.12 long, 0.02 to 0.25 broad.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.