COLLECTION OF SHELLS. 617 



The family of the conchas comprehends one 

 hundred and seventy-two species, divided into 

 sea and river shells. These last compose three 

 genera ; the cjclas^ which are very small shells, 

 inhabiting our ponds and rivers ; the cyrena, 

 more especially found in India and America ; 

 and the galathea, a very valuable shell from Cey- 

 lon. The sea or marine concha, of which there 

 are more than a hundred and sixty species, are 

 distributed into four genera, the cyprina, the 

 c/therea, the venus, and the venericardia. The 

 venericardia is known only in a fossil state ; it 

 is very common at Grignon and throughout 

 Champagne. There are more than seventy spe- 

 cies of the genera cytherea and venus, all very 

 remarkable from their form and the variety of 

 their colours. »The rarest among them are the 

 v. erjcina, the v.dionoB, the v.plicata, the v. la- 

 mellata, which are all foreign; and the v. de- 

 em sata, known in Provence under the name of 

 clovis, 



The cardiacea consist of more than one hun- 

 dred and fifty species, divided into five genera, 

 of which the cardium, is the most numerous. It 

 is seldom that the two valves of the cardium cos- 

 latum are found belonging to the same individual : 

 the specimen in the Museum is of an uncommon 

 size. The c. ceolicum, cardissa, junonioB, and unedo 



