ANODONTA SUBORBICULATA. 



SPECIFIC CHARACTFR. 



Suborbiciilar, a little ^viiigcd. 



DESCRIPTION. 



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Ovate-orbicular, rather compressed ; pale olivaceous 

 tinted with flesh colour ; with very slender, almost capil- 

 lary, and very numerous, obsolete greenish radii ; some- 

 times with more or less obvious, transverse, yellowish bands 

 towards the base ; beaks not elevated above the general sur- 

 face, with two or three rows of very small tubercles : limine 

 margin nearly rectilinear, compressed behind, and anteri- 

 orly compressed almost into a wing : ligament^ particular- 

 ly in the young specimen, concealed : posterior margin 

 rounded : anterior margin a little prominent, obtusely an- 

 gulated ; basal margin much arquated : U'ithin undulated 

 almost as obviously as on the exterior ; pale bluish, varied 

 with pale tlesh colour, and somewhat iridescent before and 

 behind : cicatrices slightly impressed. 



Length about four inches. 



Breadth five and three-tenths. 



Convexity nearly one inch and three quarters. 



A large and fine species. Some time since, Mr. O. Ev- 

 ans obtained an individual, Avhich I hesitated to publish as 

 new, thinking it might possibly be a young remote variety 

 of the A. grandis, Nob. but subsequently, having receiv- 

 ed adult and perfect specimens from Mr. Evans, I found 

 that it is uniformly longer, more rounded, much more 



PLATE XI. 



