1398 THE VOYAGE OF H.M.S. CHALLENGER. 



Cephalis large, trilobed, with a short, oblique horn of half the length. Thorax campanulate, conical, 

 separated from the abdomen by a circle of smaller pores and a deep stricture. Abdomen flat, dis- 

 coidal, with three circles of larger pores. 



Dimensions. — Length of the three joints, a 0-02, b 0-04, c OM ; breadth, a 0-06, h 012, c 018. 



Habitat. — Fossil in Barbados. 



4. Theocalyi^tra cornuta, Haeckel. 



Carpocanium cornutum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 287, Taf. ii. 



fig. 9. 

 Hdlicalyptra cornuta, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. xxii. p. 5, pi. i. figs. 13, 14. 

 Lophophmna cornuta, Haeckel, 1862, Monogr. d. Radiol., p. 299. 



Shell campanulate-conical, with two sharp strictures. Length of the three joints = 1:3:1, 

 breadth = 1:4:5. Cephalis subspherical, with two stout, pyramidal, divergent horns of twice the 

 length. Thorax campanulate, with eight to ten transverse rows of roundish or nearly square pores, 

 increasing in size towards the abdomen, which is flatly expanded, nearly discoidal, separated by a 

 circle of smaller pores ; the last circle of pores (on the margin) is larger. 



Di'mensio7is. — Length of the three joints, a 0'025, b 0'09, c O^OS ; breadth, a 0'03, b 012, c 016. 



Habitat. — Arctic Ocean, Kamtschatka (Bailey), Greenland (Ehrenberg). 



Genus 612. Cecryphalium,^ Haeckel, 1881, Prodromus, p. 434. 



Definition. — Theocorida (vel Tricyrtida eradiata aperta) with discoidal or flatly 

 expanded abdomen. Cephalis without horn. 



The genus Cecry2)halium has the same flat, conical, or nearly discoidal shell as the 

 preceding Tlieoccdyptra, its ancestral genus, but difl^ers from it in the complete absence 

 of horns on the cephalis. 



1. Cecryphalium lamprodiscus, n. sp. (PI. 58, fig. 2). 



Shell flatly conical, with two slight strictures. Length of the three joints = 1:3:2, breadth = 

 1 : 7 : 11. Cephalis roundish, very small. Thorax conical, with straight lateral outline ; its pores 

 irregular, polygonal, increasing in size towards the girdle. Abdomen Kttle flatter than the thorax, 

 forming its direct prolongation, with five to six circular, concentric rows of pores ; the first row 

 formed by sixty to eighty very large, oblongish, quadrangular pores, the second row by very small, 

 the third again by larger pores ; the outmost rows by very small and numerous pores. 



Dimensions. — Length of the three joints, a 0-02, b 0-06, c 0-04 ; breadth, a 0-02, b 014, c 0-22. 



Habitat. — Central Pacific, Station 272, surface. 



1 Cecryphalium = Net-cap ; xexjwpaXio*. 



