52 GENUS IV. MYA. 



M. Menard has separated another, which is adopted by 

 Mr. Parkinson, as well as the four of Lamarck's, viz. 

 Panop^j. Shell transverse, inequilateral, gaping unequally 

 at the ends. Hinge with an elongated tooth, under the 

 cartilaginal depression in both valves on the interior 

 edge ; a conical hinge tooth, rather flat and bent, and 

 on the right valve a little pit which receives the tooth 

 opposite, the cartilage external. Two muscular impres- 

 sions in each valve towards the extremities (see Mya 

 Glycetneris, Born, Mus. t. 1. f. 8). 



