SPONDYLUS THORNY OYSTER. Ml 



transverse lines ; margin crenated ; colour grey, 

 or ivory white, variously marked with chesnut 

 brown spots, the area and areola are of the same 

 colour as the spots ; diameter about an inch. 



Found on the shores of Germany, America, 

 and the East Indies. 



Genus - SPONDYLUS.* (Plural, Spondylt. ) 



THORNY OYSTER. 



Generic Character. Shell bivalve,inequivalve, 

 inequilateral, fixed, strong, solid ; surface coarse 

 and rough, with either lamellar or subulate 

 spines ; the hinge has two strong recurved teeth 

 in each valve, with an intermediate sinus for the 

 ligament; the lower valve is convex, and is 

 produced at the apex into a projecting beak 

 which appears as if it had been sliced off by a 

 sharp instrument, presenting a triangular flattened 

 surface, having a groove which receives the 

 decaying part of the ligament. The shell is 

 often eared. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The shells of this genus are remarkable, not 

 * Plate VIII. figures 9, 10. 



