CYTHEREA. 



Lam. 



TESTA bivalvis, aeqiiivalvis, plerumque plus mi- 

 nusve inaequilateralis ; vel obtuse trigona, vel 

 ovalis, vel lenticularis ; laevis vel conceiitrice, 

 vel radiatim striata ; dentihus utriusque valvae 

 cardinalibus tribus vel plurimis, divergentibus ; 

 laterali unico, antieo, plus minusve approxi- 

 mato. 



The Linnean Geinis Venus consisted of an immense 

 assemblage of shells remarkably different in their charac- 

 ters, and in the habits of the animals by which they have 

 been formed. That the Cytherea should have been asso- 

 ciated with the typical Veneres of Lamarck is not surpriz- 

 ing, because their general appearance is much alike, but 

 the decided separation of Lucina, Corhis, Megadesma,^ 

 and Cyrena seems to be fully warranted by the great dif- 

 ferences in their general characters. We apprehend that 

 the time is not far distant when the establishment of seve- 

 ral well-marked groups of smaller extent, will, under new 

 generic appellations, be thought desirable. Taking Cythe- 

 rea lusoria of Lamarck as typical, and associating with it 

 such other species as accord well with that in general cha- 

 racters, we shall still find that several very different forms 

 have been associated together, even in the Genus Cytherea 

 as it stands in Lamarck. We feel obliged to state that, in 

 our opinion the Veneres and CytherejBe require a most 

 careful revision ; and that all the species should be arranged 



* Galathea, Lam. 



