364 MOLLUSCA. FISSURELLAD^. Fissurella. 



Shells, t. xxi. f. 1. Mont. Brit. Shells, 486. — On rocks and shells in 

 rather deep water. 



Breadth sometimes reaching to an inch and a half; white, with a carna- 

 tion tinge ; cuticle brown, rough with a pilose margin ; aperture round, 

 slightly waved. 



360. C. antiquatus. — Apex blunt, the layers of growth form- 

 ing concentric scale-like wrinkles. 



Patella rugosa, List.. Conch, t. Dxliv. f. 31. ? — P. ant. Linn. Syst. i. 1259. 

 Pult. Dorset. 51.— Mont. Test. Brit. 485 — On different parts of the 

 coast, rare. 

 Breadth about half an inch ; thick, opake, white, apex variable in form; 

 aperture oval or round. 



— 361. C. militaris. — Shell decussated by longitudinal and 

 transverse striae. 



Patella alba, List. Conch, t. oxliv. f. 32 — P. mil. Pult. Dorset. 51. Don. 

 Brit. Shells, t. clxxi. Mont. Test. Brit. 488. t. xiii. f. 11.— On diffe- 

 rent parts of the coast, rare. 

 Breadth about half an inch ; subpellucid, white ; cuticle brown, pilose ; 

 apex much reflected and recurved ; aperture round ; inside glossy white. 



EXTINCT SPECIES. 



1. C. unguis Depressed, suborbicular, obscurely radiated ; vertex ob- 

 lique, recurved, extended beyond the base, acute. — Patella unguis, Sower. 

 Min. Conch, t. cxxxix. f. 7-— In Crag, Holywell. 



FISSURELLADiE. 



Gen. LXXXVIII. FISSURELLA.— Shell ovate, conical, 

 with a perforated apex ; tentacula with eyes at the external 

 base. 



362. F. grceca. — Oval, decussated by unequal longitudinal 



ribs and transverse stria? ; apex truncated. 



Patella cancellata, List. Conch, t. Dxxvii. f. 2. — P. graeca, Linn. Syst. i. 



1262 Penn. Brit. Zool. iv. 144. t. lxxxix. f. 153 P. reticulata, 



Don. Brit. Shells, t. xxi. f. 3. — Western coasts, not common. 



Length of the aperture about three quarters of an inch, breadth half an 

 inch ; height a quarter ; thick, brown, inside white or rayed with brown ; 

 perforation of the apex oblong ; margin of the aperture waved, crenulated. 



363. F. apertura. — Conical, with a reflected subspiral apex. 

 Patella apertura, Mont. Test. Brit. 491. t. xiii. f. 10. — South of England 



and Zetland. 



Length about §ths, height |th, subpellucid, white, strong, the longitudinal 

 tubercled ribs crossed by a few circular ridges ; apex adhering, the perfora- 

 tion in front rhomboidal ; margin of the aperture oval, crenated by the ribs. 



