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CHAPTER XVII. 



OF THE OSTREA. GENUS XIV. 



OSTREA. 



"Animal a Tithi/s. Shell bivalve inequivalved, somewhat eared; hinge 

 without teeth, with a little ovate hollow and lateral transverse stria." — 



LiINN. 



LiNNiEUs makes four divisions of this genus, which inchides 

 both Scallops and Oysters. The first division consists of 

 Scallops with the ears on each side, the beaks equal ; the 

 second division contains those that have one ear fringed as it 

 were with spines, and generally unequal ; the third has the shell 

 on one side of the beaks more gibbous or swelled larger than 

 the other ; and the fourth consists of rough ones, or those com- 

 monly called Oysters. 



The Scallops or Pectens have at the hinge a small hollow, 

 nearly ovate or somewhat triangvilar, under the beaks in each 

 valve, which hold the connecting cartilage Q]il. 4. /. 41. a), 

 but have no teeth ; the cartilage of course is internal ; there 

 is on both sides of the beaks in each valve a somewhat trian- 

 gular appendage or extension of the shell, called an ear Qpl. 4. 

 /. 41. bU). In some species, as Ostrea maxima, Jacobea, &c., 

 the ears on each side the bealcs are nearly equal : these are 

 placed in the first division. In some, as Ostrea varia, Pallium, 

 &c., the ears on one side the beak in each valve are much 



