PLATE CL 



MYA DEPRESSA. 



DEPRESSED MTA. 

 GENERIC CHARACTER. 



Animal an ascidia. Shell bivalve, gaping at one end. The hinge 

 for the most part furnished with a thick, strong, and broad tooth, 

 not inserted into the opposite valve. 



SPECIFIC CHARACTER. 



Somewhat ovate, anterior part rather wedge-shaped and sloping : 

 a slight depression across the middle ; posterior part roundish, gaping. 

 Teeth at the hinge crenulated. 



My A Depress a : testa subovata, antice sub-cuneiformi declivi, medio 

 depressa, postice rotundata hiante, cardinis dente 

 crenulato. 



After comparing the numerous kinds of fresh water Myse found in 

 different parts of the kingdom, the conchologist will perhaps be sur- 

 prized at the small number we shall venture to admit as distinct 

 species. The varieties of those Shells seem endless, and it may be 



g 4 



