812 cecid^e of the 'challenger' expedition. [Dec. 16. 



glass. At about one third from the apex they are replaced by 

 irregularly disposed striations. Towards the mouth the shell is 

 slightly dilated ; but just at the edge it is faintly constricted and then 

 even more faintly reflected. The septum is minute and very slightly 

 elevated in the form of a centrally mamillated button. 



The species differs from C. lipartitum (' Les Fonds de laMer,' vol. i. 

 p. 185, pi. xxv. figs. 9, 10) from Mexico, in size, thinness of shell, form 

 of mouth and septum, and in sculpture. From C. semicinctum (Les 

 Meleaginicoles, p. 42 ; Les Fonds de la Mer, p. 8) it differs in size, 

 thinness, arrangement and form of the rings, and in the form of its 

 septum. 



<Sj j- q 15. Cecum crystallinum, n. sp. 



July, 1875. Reefs off Honolulu. 40 fms. One specimen. 



Length ? Breadth 0*3 mm. 



An imperfect specimen, the upper part being broken off. It is 

 evidently a new species, though nearly related to 0. striatum (Fonds 

 de la Mer, vol. i. pp. 49, 170, pi. v. fig. 3), from which it differs in that 

 the shell towards the mouth expands and is thereafter contracted so 

 as to form a minute gorge, with a slightly reflected lip. At first sight 

 it resembles C. glabriforme, Carp. (Brochina) ; but it is straighter, 

 and the texture of the shell is different, exhibiting under the micro- 

 scope fine longitudinal striations. Though unable, from its imperfect 

 condition, to offer a full description, the specimen is so clearly a new 

 species that I venture to attach to it the name I have given above. 



