I860.] Contributions to Indian Malacology. 141 



No. 10. — Unio Bengalensis, Lea. Bengal. 



Lea, Trans. Am. Phil. Soc. VI. 3, pi. 2, f. 3. 

 Kiister, Mart, and Chem., p, 228, pi. 77, f. 2, 3. 



In this case again, two totally distinct shells are figured, and again 

 the authority for Krister's appears to be Dr. von dem Busch, whose 

 collection furnished the specimen figured in Martini and Chemnitz. 

 Lea's type is a very peculiar variety of U. marginalia, very much 

 11 longer" (that is wider when measured from the umbones to the 

 ventral margin) in proportion to the breadth than usual. I have not 

 met with it. It was obtained by Lea from Dr. Burrough who pur- 

 chased it in Calcutta, and believed that it inhabited the Granges, It 

 has better claims to distinction than most of Lea's " species."* 



Krister's type is a much thicker, more tumid shell, with far 

 stronger teeth and impressed cicatrices, much more inequivalve and 

 different in almost every character. I cannot recognise it as any 

 form with which I am acquainted, and I much doubt its being Indian 

 at all. At all events it is nearer to U. corrugatus than to U. mar- 

 ginalis. 



No. 11. — Unio lamellatus, Lea. Bengal. 

 Lea, Trans. Am. Phil. Soc. VI. 19, pi. 6, f. 16. 



This is another variety of the U. marginalis type, perfectly inter- 

 mediate between the two last named, and approaching the type more 

 nearly than either. Lea's shells were probably immature. In the 

 younger shells of marginalis, the hinge teeth are more lamellar than 

 in the adults, and the principal character of this " species" and of the 

 two preceding is the lamellar teeth. 



I have not met with the exact type of this shell, but it doubtless 

 inhabits the neighbourhood of Calcutta. Specimens resembling it in 

 every way except in being rather less long (in the dorso-ventral dia- 

 meter) in proportion to their breadth are common. 



No. 12. — Unio Rajahensis, Lea. Rajah's Tank, Calcutta. 



Lea, Trans. Am. Phil. Soc. VIII., 239, pi. 23, fig. 53. 



The above is the locality quoted. I am unable to discover what 



* In a letter to my brother, Mr. Benson suggested a doubt as to whether 

 this species were Indian. Taking into consideration the circumstance that 

 nearly all the shells in the Calcutta bazar are foreign, this suggestion appears 

 highly probiible. 



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