124 



obj|ptioii to Lamarck's separation of it. See No. 6, 

 of his Genera of Shells. 



Gryphaea angulata 

 [And eleven fossil species.] 



OSTREA. 



OSTREA EDULIS. COMMON OYSTER. 



Sowerbys Genera, No. 6, pi, 3. 



The genus Ostrea, as it now stands, is a very natural 

 and well-defined association of shells. Bruguiere was 

 the first to divide the G. Ostrea of Linnaeus into seve- 

 ral new genera, to which Lamarck has added others, 

 as will be seen by an attentive comparison of the 

 illustrative examples given to each genus in this 

 arrangement; of which Pedum, Pecten, Gryphaea, 

 and Vulsella, were all considered Ostreae by Linnae- 

 us. And notwithstanding the numerous divisions now 

 made, Lamarck observes, that those which have the 

 valves plain and united, and those which have them 

 plaited or angular, might still be made into twosections; 

 but the irregularity of these shells renders the determi- 

 nation of their species often very difficult. Shell adhe- 

 sive, inequivalve, irregular, summits distant, becoming 



