38 



* P. VARIUS. Ostrea V. Tart. Lin. Pecten V. Pen. 

 Brit. Zo., vol. 4, pi. 61, fig. 64. Mont. Test. Brit,, vol, 1, 

 p. 146. Fiem. Brit. An., p. 384. Less abundant. 



P. LINEATUS. Mont. Test. Brit., vol. 1, p. 147. Flem. 



Brit. An., p. 383. Scarcely common. I have only seen 



it at Falmouth. 

 P. OBSOLETUS. Ostrea O. Tart. Lin. Pecten O. 



Pen. Brit. Zo., vol. 4, pi. 61, fig. 66. Flem. Brit. An., 



p. 385. Rare. 



* P. LEVIS. Ostrea L. Pecten L. Pen. Br. Zo., vol. 4, 

 102. Mont. Test. Brit., vol. I, p, 150, pi. 4, fig. 4, This 

 very pretty shell is not uncommon ; but is subject to great 

 variety of colour, though always beautiful. 



* P. SINUOSUS. P. Pusio. Pen. Brit. Zo., vol. 4, pi. 61, 

 fig. 65. P, Distortus. Mont. Test. Brit. vol. 1, p. 143. 

 P. S. Fiem. Brit. An., p. 384. By Sowerby constituted 

 the type of the Genus Hinnites. Common, attached by 

 the lower valve to rocks, or more frequently to eschara 

 foliacea. It is subject to apparent distortion in its growth; 

 but it acquires the length of about a quarter of an inch 

 before the irregularities begin, and afterwards becomes 

 waved without regard to the evenness of its situation. It 

 may be known at any stage by the ribs dividing in their 

 progress, into smaller striae, of nearlv alternate sizes. 



P. TUMIDUS. Flem. Brit. An., p. 314, described from 

 Dr. Turton. Not uncommon on the shell of the pinna, 

 but overlooked from its minute size. In their young state 

 the Pectens are moored to their situation by a byssus; but 

 when loosened by accident or nature, it is not renewed, and 

 they are capable of some degree of motion, 

 OSTRACEA. 



Ligament wholly or partly within. Shell irregular, foliated, 

 sometimes very thin. 



OSTREA. 



GENERIC CHARACTER: The shell adhering, valves 

 unequal, irregular; beaks distant, becoming very unequal 

 by age; upper valve smallest, generally fiat, and gradually- 

 advancing forward during the life of the animal. Hinge 

 without teeth. Ligament partly internal, inserted in the 

 cardinal pit of the valves ; pit of the lower valve increasing 

 by age, sometimes to a great length. 



* O. EDULIS. Turt. Lin. Pen. Brit. Zo., vol. 4, p. 102. 

 Mont. Test. Brit., vol. 1, p. 151. Flem. Brit. An., p. 392. 

 Oyster. Common on most parts of our coast?, and at all 

 depths. It is found on the Pinna at the degth of 50 fa- 

 thoms. The oyster is cultivated for sale on the Tamar, 

 at Falmouth and He! ford. 



O. PARASITICA. Flem. Brit. An., p. 392. Less common. 



