44 



had not changed its situation, from an early stage of 

 growth. I have also obtained it, of small size, from ihe 

 stomach of a fish. 



* P. MILITARIS. Patella M. Mont. Test. Brit., vol. 2, 

 p. 488, pi. 13, fig. 11. Capulus M. Flem. Brit. An. p. 364. 

 At various parts of the coast, but scarce. 



P. ANTIQUATUS ? Montagu describes this shell (Patella 

 Antiquata) as liable to great variation ; under which it is 

 not in*probable that more than one species is included. 

 My specimen, which was attached to a Pinna, was about 

 aline in its longest diameter; texture thin, and in parts 

 nearly transparent : longitudinal lines from the point to the 

 margin simple, causing the edge to be angular; crossed in 

 their progress by circular ridges, seven in number, inclined 

 towards the margin. Curve of the cap to the right, as the 

 broad expanse is placed forward : its form much as in P. 

 Hungarica, but more bent down. Colour pale yellow. 



CALYPTR^EA. 



GENERIC CHARACTER: The shell conoidal, summit 

 erect, imperforate, subacute. Cavity furnished with an 

 attached, convolute plate. 



C. SINENSIS. Patella S, Turt. Lin. P. Chinensis. 

 Mont. Test. Brit., vol.2, p. 489, pi. 13, fig. 4. C. Ch. 

 Flem. Brit. An., p. 362. Found on oysters at Helford, 

 and generally wherever native oysters are dredged ; but 

 soon falling off spontaneously, it escapes observation. 



ANCYLUS. 

 GENERIC CHARACTER. The shell ovate, conical, 

 simple, the tip central, posterior, rather obliquely re- 

 curved to the right; cavity with a lunate submarginal scar, 

 interrupted on the left side. This genus is by Gray, 

 classed with the Limnaeadae, on account of the form of the 

 animal inhabitant. The shell, continues Mr. Gray, from 

 whom the generic character is derived, differs from 

 Siphouaria, with which alone it can be confounded, on 

 account of the peculiar form of the muscular scar, and the 

 lateral situation of the apex ; in being thin and pellucid ; 

 only finely striated and covered with a thin olive perios- 

 traca. It only agrees with Patella in the outward 

 appearance of the shell, for in that genus the apex is 

 anterior, and in this it is posterior, as in most univalves. 



* A. FLUVIATILIS, Patella F. Mont. Test. Brit, vol. 2, 



p. 482. Flem.- Brit. An., p. 280. Gray's Turton's Manual, 

 p. 249, pi. 10, fig. 125. Common on stones, in rivulets. 



BULLAE AN A. 



Either without a shell ; or the shell without columella, 

 or projecting spire; inflated; aperture large, the length of 

 the shell. 



