287 



Fig, 207. Caprinella triangularis, Desm. U. Green-sand, Rochelle. 

 A, portion of the left valve, after D'Orbigny,* the shell-wall is removed byweather- 

 ing, exposing the camerated interior. B, mould of five of the water-chambers. C, 

 mould of the body-chamber ; u, umbo of right valve ; s, of left valve ; t, dental groove : 

 a, surface from which the posterior lobe has been detached. From the originals in the 

 Brit. M. presented by S. P. Pratt, Esq. -> 



CAPRINELLA, D'Orbigny. 



Type, C. triangularis, Desm. (Fig 207). Syn. Caprinula (Boissii) D'Orb. 



Shell fixed by the apex of the right valve, or free ; composed of a thick 

 layer of open tubes, with a thin compact superficial lamina ; cartilage inter- 

 nal, contained in several deep pits ; umbones more or less camerated ; right 



Fig. 



Fig. 208. Straight valve. Fig. 209. Spiral valve. 



Transverse sections of C. Boissii, L. Chalk, Lisbon (Mr. Sharpe). 



I, position of ligamental inflection; t, teeth; c, cartilage pits; u, umbonal cavity. 



ig. 209 is from a weathered specimen, which has lost the outer layer. The tubes of 



the shell-wall are filled with limestone containing small shells. 



