1923. j Ostrea gryphoides Schlotheim in Calcutta, 79 
and it is very remarkable that these large oyster shells have 
not been reported from any of the numerous excavations 
and bores made in Calcutta city and its neighbourhood within 
recent years. The shells themselves are of striking appearance 
and it is unlikely that they would be passed unnoticed. 
Small freshwater and estuarine gastropoda are often found 
below the present surface in Caleutta. Velescopium fuscum 
was met with in excavations near Presidency College and 
a few molluscs obtained lately by the writer, 3 feet below the 
evel of Free School Street. were pronounced by Dr. Annandale 
to be identical with forms living in Calcutta tanks to-day. 
The last discovery, in the absence of further evidence, has 
left the problematical origin of the Clive Street oyster bed 
precisely where it was before and the reader must be left to 
judge for himself whether it is of marine origin or not. 
he new examples consist of two separated valves form- 
ing one shell, the lower valve of which 
has the upper end of the ligamental area 
broken off, and of one practically complete 
lower valve. Both are adult specimens. ‘The dimensions of 
the single lower valve compared with those of one of the 
earlier examples are given below. 
Description of the 
New Shells. 
Present specimen. Earlier specimen. 
tow height=31 cm. 38 cm. 
Ie Meade te Gitte OME TT ee Se 
Height ot hinge-area =15_,, Soe 
Width se es ns = 8 = Pe. 
have compared the specimens with the figures of those 
described by Messrs. Bullen Newton and Smith, with other 
examples from Calcutta excavations, and with recent shells 
from the Mergui coast of Burma. Further, [ have compared 
them with the fossil forms known as Ostrea crassissima from 
dinal strie, The recent specimens from the clear waters of 
the Bay of Bengal have very much smaller ligamental regions 
than those from the muddy waters of an estuarine environ- 
the great thickness of lower valve, which attains 5-8 cms. 
through the ligamental furrow in one specimen, indicate 
