CERATOPHYSA CERATOPYGA. 127 



numerous and have short but distinct necks. The valves (PL 145, fig. 2) are 

 about .15 mm. long, rather wide and flat and finely serrate on the margin. The 

 tridentate or rostrate have the valves (PL 145, fig. /) less flat, more elongated 

 and more pointed; they are about .35-40 mm. long but show considerable 

 diversity in size as well as in form. The ophicephalous are well figured by 

 Mortensen. The Albatross took specimens of Cystocrepis at three stations 

 in the Panamic region, at depths of 1573-1879 fms. 



Spatagocystis. 



A. Agassiz, 1879. Proc. Amer. Acad., 14, p. 206. 

 Type, Spatagocystis challengeri A. Agassiz, 1879. hoc. cit. 



The Challenger collected Spatagocystis in the extreme south of the 

 Indian Ocean in 1600-1950 fms. It has not been met with since. 



Ceratophysa. 



Pomel, 1883. Class. Meth. Ech., p. 40. 

 Type, Pourtalesia ceratopyga A. Agassiz, 1879. Proc. Amer. Acad., 14, p. 205. 



This genus contains two species both collected by the Challenger and 

 not since taken. Neither is known from adequate material and it is quite pos- 

 sible that they are not congeneric. 



Key to the Species of Ceratophysa. 



Anal rostrum rounded ceratopyga. 



Anal rostrum laterally compressed, truncate rosea. 



Ceratophysa ceratopyga. 



Pourtalesia ceratopyga A. Agassiz, 1879. Proc. Amer. Acad., 14, p. 205. 

 Ceratophysa ceratopyga Pomel, 1883. Class. Meth. Ech., p. 40. 



This species is one of the largest of the family. Mr. Agassiz estimated 

 from fragments that it attains a length of nearly 200 mm. It was taken by 

 the Challenger in the Antarctic Ocean and off the coast of Chile at depths 

 of 1950-2225 fms. 



