617 



Shell of a subovate trigonal form, thin, smooth, the hinder 

 side longer than the front ; the umbones bluish aud small. Colour 

 pale ashy-buff, with one strong spot of brown near the liinder 

 angle, and, in one specimen, a number of interrupted brown rays. 



Of the two specimens in the collection of Mr. Hauley, the 

 locality is unknown. 



17. Cyther^a trigonella (pi. cxxviii. f. 16), Lamarck, 

 Anim. s. vert, no, 28. Trigona angulifera, GraT/, in Analyst, 1838. 



Cyth. "testa trigona, subsequilatera, depressa, pallide fulva; 

 radiis albis, raris; ano lanceolate." — Lamarck. 



The specimen figured is very much like that in Delessert (t, 8. 

 f. 3) ; and this is the only means of identification, as the above 

 description w^ould apply to several. It is oblong, trigonal, almost 

 transparent, nearly equilateral; at the hinder side it is rather 

 squared and has a dark brown band. There is a red softened 

 spot on either side of the umbones, wliich are small, and the body 

 of the shell is variously coloured with pale rays and several zig- 

 zag brown markings. 



West Indies. 



18. Cythee^a incerta (pi. cxxviii. f, 17), Sowerhy , jun. 



Cyth. testa alba, Isevi, ventricosa, ovaU-subtrigona ; umbonibus 

 parvulis, utrinque rubro-tinctis ; lineis pallidis, fulvis, angulatis, 

 sparsis. 



A small, white, ovate-subtrigonal shell, resembling C. trigonella, 

 but more obese and thick, and not so decidedly oval. 



St. John^s ; M. Ilartweg. We have only seen the specimen in 

 Mr. Cuming's collection. 



19. CyTHER^^A BicoLOR (pi. cxxvii. f, 10, 11), Gra^, in 

 Analyst. Hanky, Sp, of Shells, Wood, Suppl. pi. 15. f. 16. 



Cyth. testa trigona, angulata, alba, post angulum castanea, 

 alta, compressa ; lateribus et margine ventrali rectis ; latere pos- 

 tico subelongato, acutiusculo ; lunula elongata, distiucta ; um- 

 bonibus acutis. 



A white shell, with a dark brown mark beliind the angle, rather 

 compressed, and nearly approaching an equilateral triangle in 

 form, the hinder side being a little longer and more acute. 



The brown specimen is from the Red Sea, in Mr. Cuming's 

 collection. 



Senegal. 



4l 



