660 Notes of some Land and Fresh Water Shells, fyc. [July, 



generality however, measure less, being 1 T X ¥ in. wide and |f in. in 

 height. It is strongly furrowed transversely ; with olive brown epi- 

 dermis and beaks denuded. 



Var. A. Also found in the Gangetic Provinces ; smaller than the 

 last, being in breadth -J in. by if in. high, transversely furrowed ; 

 epidermis yellow, or sometimes greenish, half way from the beaks, with 

 a broad yellow border ; inside violet or purple, as in the last, of which 

 this may be the young. 



Fam. Unionid^e. 

 21. — Unio marginalis, (Lam.) 



Shell oval oblong, ventricose, tumid ; not produced nor attenuated 

 behind ; beaks flattened and denuded ; upper edge rounded or falling ; 

 lower edge curved ; strongly wrinkled transversely ; epidermis olive 

 brown ; in young specimens with broad yellowish margin. Largest 

 specimen measuring lf£ in. long, by 2|f in. broad; another l|f in. 

 by 2i| in. ; and a third measures 1^-f in. long, by 3 T ^ in. wide. 



Occurs at Candahar in canals. 



Mr. Benson thought this only a strong variety of U. marginalis of 

 Lamarck, and in deference to his opinion I have so named it ; at the 

 same time I am much inclined to think it distinct, and propose, should 

 it prove so, to call it U. Candaharicus. The differences observable 

 appear to consist in the less produced and lengthened form posteriorly, 

 — in the upper part of the anterior edge being straighter and more 

 elevated, than in U. marginalis, — and in the beaks being less denuded 

 and more wrinkled. 



In XJnio marginalis of the Gangetic provinces, the breadth appears 

 to exceed the length much more considerably than in the Candahar 

 shells, measuring in four specimens of each as follows : — 



1. Indian specimen. Length 1 T 6 ^ in. ; breadth 3 T 2 ^ in. 



2. Ditto ditto length l\% in. ; breadth 3f in. 



3. Ditto ditto length l T \ in. ; breadth 3 T 2 ^ in. 



4. Ditto ditto length 1^ in ; breadth 3 in. 



1. Afghan specimen. Length \° s in. ; breadth 2ff in. 



2. Ditto ditto length l|f in. ; breadth 2f£ in. 



3. Ditto ditto length lif in. ; breadth 2|f in. 



4. Ditto ditto length 1 jf in. ; breadth 3 T V in. 



The proportions thus appear to be reversed, — the Indian species show- 



