J08 



MYOCONCHA. 



Gen. Char. A very unequal sided, but equal- 

 valved, oblique bivalve ; hinge with an ex- 

 ternal ligament, and one elongated, oblique 

 tooth in the left valve ; beaks close to the 

 posterior extremity ; no sinus in the impres- 

 sion of the mantle. 



A. VERY remarkable Genus, in general form resembling 

 Modiola, but bearing a close affinity to Astarte (Crassina 

 Danmoniensis Lam.) and the Conchas generally of 

 Lamarck. The support of its hinge Ligament* is very 

 prominent ; it has no lateral teeth ; the posterior side or 

 lobe is almost wanting ; the surface has no ribs ; the 

 three last characters distinguish it from Cardita, the im- 

 pression of the posterior muscle is deep. 



Only one species is known. The Generic name im- 

 plies its resemblance in form to a Mouse or Muscle, 

 together with its affinity above alluded to. 



MYOCONCHA crassa. 

 TAB. CCCCLXVJl. 

 Spec. Char 



^HELL ovate, slightly curved, pointed at one end, con- 

 vex, nearly smooth, thick in substance : in the young 

 state there are 3 or 4 longitudinal elevated striae, crossed 



* I propose to call this part the Julcrum, in place of a term generally 

 considered objectionable, and also because it may apply to the sartie part 

 whether it be elevated or not. 



