556 Journal of the Asiatic Society of Bengal. [N.S., XVIII, 
settling on the bricks and commencing their boring operations 
by ‘an inequality of the surface produced by the falling out 
from the bricks of small pieces of cinder incorporated in their 
substance. The burrows were bottle-shaped and penetrated 
the brick to a depth of about 4 cm. In one, of which a 
vertical section was obtained, the entrance on the surface was 
only a little more than 1 mm. in diameter, but the diameter at 
the base was 17 mm. The diameter increased gradually from 
above downwards. The shell fitted rather tightly into the base 
of the burrow and the animal of course could not possibly have 
emerged. The burrows were closely aggregated and sometimes 
one penetrated another. The direction of some was straight 
into the brick, in others slanting. 
. fluminalis, which is common in the deltas of the 
Ganges and Irrawadi, usually bores in wood but was originally 
found in soft argillaceous sandstone. 
few systematic notes as to the species collected may 
be given. 
Scaphula deltae Blanford. 
1868. Scaphula deltae, Blanford, Journ. As. Soc. Bengal 
XXXVI (2), p. 71, pl. xiv, figs. 7-10. 
Several specimens, living and dead, were found attached 
_ by their byssus in empty burrows of M. fluminalis in the 
bricks, so deeply covered by a slimy dark green alga that their 
presence was not detected until it had dried up. The species, 
which is doubtfully distinct from §. celox Benson, is common 
in the lower reaches of both the Ganges and the Irrawadi 
and also occurs high up the Mahanadi at Sambalpur in the 
interior of Orissa. 
Corbula gracilis Preston. 
1907. Corbula gracilis, Preston, Ann. Mag. Nat. Hist. (7) 
5 
ALA, p. 215, fig. 4. 
1911. Corbula chilkaensis, id., Rec. Ind. Mus. VI, p. 39, 
fig. 2. 
A single empty shell was found inside one of Martesia 
fluminalis in a brick. It is rather larger than the type- 
specimen and both in size and other characters seems exactly 
intermediate between that specimen and the type-specimen of 
the same author’s C. chilkaensis, which must be regarded 
as synonomous with C. gracilis. 
: les is very near my C. mesopotamica, but apart 
from slight differences in outline, has the hinge-teeth much 
less produced. 
In the Gangetic delta molluscs of this genus frequently 
make their way into the burrows of Teredinidae in w d 
also into the exhalent canals of the sponge Spongilla alba. 


