138 Contributions to Indian Malacology. [No. 2, 
M. testé ovali rugosd, extrinsecus virescente, intus margaritacea : 
cardinis dente primario crenulato, laterali longitudinali, alterius 
duplicato. 
No. 3.—Unio maretnatis, Lam. Bengal. 
Lam. VI. 79, No. 41. 
Kiister, Mart. and Chem. p. 239, Pl. 80, f. 4, 
This species is probably the most widely distributed of all the 
Indian forms. It is extremely variable, and I am inclined to believe 
that many of the species to be hereafter enumerated are merely 
varieties of it. I have examined the type and compared a shell from 
Pegu with it, which will be figured. It agrees very well. Kiister’s 
figure represents a variety with unusually prominent umbones, and 
rather longer from the hinge to the ventral margin than usual. 
U. marginalis is by no means confined to India. It abounds, as I have 
already mentioned, in Pegu. One of Lamarck’s forms came from Ceylon, 
and Kiister appears much disposed to unite to it a species from the Nile 
in Egypt. Lamarck’s type was said to inhabit rice-fields in Bengal. 
No. 4.—Unto anopontints, Lam. Bengal. 
U. anodontina, Lam. VI. 80, No. 47. 
U. anodontinus, Kuster, Mart. and Chemn. p. 240, Pl. 80, f. 5. 
Lea has classed this shell as identical with U. marginalis, Lam. 
Tf Kiister’s figures in the Conchylien Cabinet can be trusted, the two 
shells differ more than any one of Lea’s three species, bilineatus, lamel- 
latus, and Bengalensis do from each other, or from marginalis. Most of 
the Bengal specimens of marginalis, however, are intermediate between 
the two forms figured by Kiister as marginalzs and anodontinus. 
The locality given by Lamarck for this species is Virginia. 
I unfortunately omitted to examine the specimen when I had the 
opportunity of doing so. There is, I believe, no question but that 
the shell was really from India. 
No. 5.—Unio ravipens, Bens. Ganges valley and Burhampooter 
valley, Assam. 
Benson, Gleanings in Science, I, Pl. 8, f. 1. 
» Ann, Mag. Nat. Hist. 1862, 3rd Ser. X. 188. 
This species has been frequently confounded with U. corrugatus, 
