1294 THE VOYAGE OF H.M.S. CHALLENGER. 



length. Thorax slenderly conical, or bottle-shaped, with little convex outlines ; three to four times 

 as long as broad, papillate, with regular, circular pores, which are included by rhombic frames, and 

 increase in size towards the mouth. 



Dimensions. Cephalis 0'004 diameter, thorax 0'12 long, O035 broad. 



Habitat. Indian Ocean (Zanzibar), depth 2200 fathoms (Pullen). 



14. Sethoconus orthoceras, n. sp. (PL 54, fig. 11). 



Gornutella orthoceras, Haeekel, 1879, Atlas, loc. cit. 



Cephalis very small, conical, hyaline, without pores, with a double internal stricture, and a very 

 short, rudimentary horn. Thorax slenderly conical, with undulate outlines, three to four times as 

 long as broad, with subregular, roundish pores, gradually increasing in size towards the mouth. 



Dimensions. Cephalis 0'02 long, O'Ol broad ; thorax 0'16 long, 0'04 to 0'08 broad. 



Habitat. South Atlantic, Station 325, surface. 



15. Sethoconus profundus, Haeekel. 



Gornutdla profunda, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B, Nr. B. iv. fig. 21. 

 Gornutella profunda, Bailey, 1856, Aincr. Jour., vol. xxii. pi. i. fig. 23. 

 Comutella profunda, Haeekel, 1862, Monogr. d. Eadiol., p. 284. 



Cephalis very small, spherical, hyaline, without pores and internal stricture, with a very short, 

 rudimentary horn. Thorax slenderly conical, with straight outlines, three to four times as long as 

 broad, with subregular, circular pores, gradually increasing in size towards the mouth. 



Dimensions. Cephalis 0'004 to O'OOS diameter, thorax 0'08 to 0'12 long, 0'03 to 0'04 broad. 



Habitat. Cosmopolitan ; Mediterranean, Atlantic, Indian, Pacific ; at various depths. 



16. Sethoconus trichostylus, Haeekel. 



t Cornutella trichostyla, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 287, 



Taf. vi fig. 2. 



Cephalis very small, conical, hyaline, without pores, with a very long, bristle-shaped, spirally 

 twisted horn, longer than the whole shell. Thorax slenderly conical, with straight outlines, and 

 very small, regular, circular pores of nearly equal size, which are separated by broader bars and 

 spirally ascending oblique crests (according to the figure). 



Dimensions. Cephalis 0'004 long, 0-002 broad ; thorax 0'06 long, 0'04 broad. 



Habitat. North Pacific (California), depth 2600 fathoms. 



17. Sethoconus lonqisetus, Haeekel. 



Cornutella longjseta, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 287, Taf. ix. 

 fig. 15. 



Cephalis very small, spherical, hyaline, without pores, with a very long, bristle-shaped horn, 



