CORBIS. 



Cuvier. — Regne anim. p. 481. 



TESTA transversa^ aequivalvis^ libera; umhonihus 

 opposite incurvis; Cardo dentibus duobus; denies 

 laterales dao, posticus ad cardiiiem propius admo- 

 tus^ anti^us remotus ; Impressiones musculares 

 simplices. 



All the species of this Genus that have hitherto come 

 under observation are transverse shells (that is, they are 

 longer in a direction tranverse to the position of their hinge- 

 teeth) : in common with many other bivalves, the umbones 

 are curved inwards, in opposite directions in the two valves. 

 There are two cardinal and two lateral teeth in each valve; 

 the posterior, or that which is on the opposite side of the 

 hinge to the ligament, is much nearer to the cardinal teeth 

 than the other, which is rather remote, but placed near the 

 termination of the ligament. This is external, but the 

 parts to w hich it is attached form a deep groove when the 

 two valves are closed; when also, a rather oblong cordi- 

 form impression immediately behind the umbones may be 

 observed. 



This Genus was established by Cuvier, and is adopted 

 by Lamarck, it is related to JLucina^ but may be distin- 

 guished from that Genus by its muscular impressions, which 

 are simple and rather oblong, but neither of them produced 

 into an elongated tongue shape; it approaches also to 

 Tellina^ but, wanting the fold of the anterior margin of 

 that Genus, it will not be confounded with it. Not many 

 species of this Genus are yet known, the only recent one 

 with which we are acquainted is a very beautiful trans- 

 versely oval, rather gibbous shell, with longitudinal striae 

 and undulated transverse furrows, and its interior margin 

 1^ crenulated ; it is the Venus fimbriata of Linnc ^ the Cor- 



