1866.] Contributions to Indian Malacology. 147 
Kiister’s type is narrower anteriorly and has rather different, coarser 
plication posteriorly, than Lea’s. It may be a different shell. 
No. 34.—Unto Nurtatiianus, Lea. Assam, teste Benson. 
Lea, Jour. Acad, Nat. Sci. Phil. IIT., 310, pl. 30, f. 25. 
The locality is simply stated to be India by Lea. Benson, Ann. 
and Mag. Nat. Hist. 1862, X., 194, states that he has received speci- 
mens from Assam. The volume containing the description of this 
shell is not procurable in Calcutta. 
No. 35.—Unto Jenxinstanvs, Bens. Burhampooter River, Assam. 
Benson, Ann, and Mag. Nat. Hist, 1862, 3rd Ser. X., 185. 
An ally of U. marginalis, distinguished by “the very tumid form, 
the sloping posterior end, absence of a wing, the short ligament, and 
the nature and position of the teeth.” (Bens. 1. c.) In the Asiatic So- 
ciety’s collection there is a shell from Bhagulpoor perhaps referable as 
a variety to this species. 
No. 36.—Unio pacuysoma, Bens. Burhampooter River, Assam. 
Benson, Ann, and Mag. Nat. Hist. 1862, 3rd Ser. X., 186. 
“ An inflated form of the ceruleus type.” (Bens. 1. c.) Mr. Benson 
also states that he has received a distorted variety from Calcutta. A pe- 
culiar tumid form which is not uncommon in Calcutta tanks is doubt- 
less referred to. It agrees generally with the description given. This 
form therefore adds one more to the Bengal list. 
No. 37.—Unio Smaracpires, Bens. Burhampooter River, Assam, 
Benson, Ann. and Mag. Nat. Hist. 1862, 3rd Ser. X., 190. 
A shell allied to U. favidens. 
Besides these forms a variety of U. favidens, Bens. (var. marcens) has 
already been quoted as occurring in Assam. Mr. Benson also records 
the receipt of a variety of U. ceruleus (J. A. 8. B. VI. 750) and of a 
small variety of U. marginalis (Ann. and Mag. Nat. Hist. 3rd Ser. X. 
186) from that region. 
TIL.—Cryton. 
No. 38.—Unto Layaront, Lea. Ceylon. 
Lea, Jour. Acad. Nat. Sci. Phil. 2nd Ser. IV., 248, pl. 36, f, 122. 
This is a shell of the marginalis type with a convex dorsal margin, 
and generally rounded outline. It appears to be a fairly distinguish- 
able form, though very close to Bengalensis and lamellatus. 
