Lam. — Syst. des Anim. sans vert. p. 136. 



TESTA transversa, insqiiivalvis, iiisequiiatera, 

 latere aiitico longiore ; regularise libera. Valva 

 altera plana, margine antico defiexo, dente imico, 

 oblongo, obtuso, postico, altera concava, eclen- 

 tula. Liga/mentmn cardinis internum, cicatriculas 

 elongatas inutraque valva affixum. Impressiones 

 musculares in utraque valva duae, distantes^ 

 iaterales. 



Shell transversely oblong, inequivalve, regular, not at- 

 tached, inequilateral, the anterior side longer and slightly 

 gaping at its extremity ; one valve, called by Lamarck the 

 upper valve, flat, its anterior margin turned downward, 

 with a single, oblong, obtuse hinge-tooth placed behind the 

 ligament ; the other valve concave, without any tooth, but 

 an indistinct cicatrice, against which the tooth of the flat 

 valve lies when the valves are closed. Cardinal ligament 

 internal, fixed in each valve to an elongated cicatrice, 

 w hich is inclined toward the anterior side of the shell. — 

 Two distant lateral muscidar impressions in each valve. 



It will soon be perceived that we differ very materially 

 from Lamarck in the number of teeth attributed to this 

 Genus. Our regard to truth obliges us to do so; and much 

 as we lament the necessity we are thus placed under, we 

 can assure our readers that we have not done it without a 

 strict examination of a number of specimens, for which 

 we are indebted to the friendship of C. De Gerville, and 

 also that w e find the characters constant in three species. 



The Tellina incEquivalvis of Linne is the type of this 

 Genus, it is the Pandora margaritacea of Lam. in his 

 teme, but, without giving any reason, he has altered its 

 specific name to rostrata in his Histoirc Naturelle; where- 

 fore we retain the former name. 



