284 



MANUAL OF THE MOLLUSCA. 



T 



Fig. 198. Longitudinal section ; upper half, §. Fig. 199. Transverse section,^- 



Hippurites cornu-vaccinum, Bronn. Salzburg. 

 /, m, n, duplicatures ; u, umbonal cavity of left valve; r, of right valve; c, c', car- 

 tilage-pits; /,/', teeth; a, a', muscular apophyses; d, outer shell-layer, Fig. 198 is 

 taken in the line d, b, of fig. 199, cutting only the base of the posterior tooth (f )• 

 Fig. 199, is from a larger specimen, at about the level d, b of fig. 198, cutting the point 

 of the posterior apophysis (a'), and shewing the peculiar shell-texture deposited by 

 the anterior adductor (a). 



of the teeth aud adductors further from the hinge-margin, to a position in 

 which the muscles must have been unusually long, unless supported in the 

 manner described. Supposing the animal to have had a small foot,* like 



Fig. 200. Hippvriies cornu-vaccinum. Vig. 2Q\. Radiolites cijUndraceus,^. 



Longitudinal sections taken through the teeth (/, t') and apophyses (a, a'). -^ 



d, outer, r, inner shell-layer; /, dental plate of lower valve; u, umbonal cavity of \ 



upper valves ; i, intestinal channel. Originals in Brit. M. ' 



* This is extremely doubtful; since p. 253 was printed, we have examined an \ 



authentic specimen of Aetheria, and find that Rang and Cailliaud's account is iucox- ] 



rect : it has no foot. J 



