1912. ] J. T. Jenkins: Indian Marine Fauna. 53 
the whole the Molluscan fauna of this area was not abundant, 
though specimens of Murex tenuispina were not infrequently met 
with. 
Of the Echinoderms, the Holothurian Aphalodactyla molpa- 
doides may be regarded as typical. 
Of the Crustacea the two commonest inedible forms were 
Thenus orientalis and Egeria arachnoides. ‘Two species of prawn 
of economic importance were found in this region, as well as an 
edible crab (Scylla serrata). 
The prawns consisted mainly of Peneus semtsulcatus and 
Peneus indicus, but they were not nearly so abundant in this area 
as off the sandy shores of Orissa (Area III), where large hauls were 
frequently made. 
As a general statement it may be said that the invertebrate 
fauna of this region was scanty. 
The fish-fauna of this muddy area off the Sunderbans is quite 
distinctive. Although the trawl was not adapted to catch surface- 
swimming forms, still Carcharias menisorrah and Chiloscyllium 
indicum were commonly taken. Of the Batoidei, 7vygon uarnak 
and Trygon bleekert were possibly more characteristic of this region 
than any other species. ‘he former is a large species of “‘ sting 
ray’’ and individuals measuring 5 feet or more across the back 
were common. On one occasion (Voyage No. 14, December, 1908) 
nearly 23 per cent. of the total catch of fish in this area consisted 
of these gigantic Batoids. Nine specimens of Tvygon uarnak 
taken near the Mutlah light vessel on this occasion aggregated 
1,360 lb., the average weight being 151 lb. and the extremes 
118 and 180 lb. respectively. This species seems to prefer a depth 
of from 24 to 25 fathoms, and in fact our general experience in 
this muddy area was that the fish-fauna was more abundant at 
this depth than on deeper or shallower areas. 
Two hauls taken close together on the same day in the same 
locality bring this contrast out very well:— 
December 20th, 1908. Near Mutlah light vessel. 
Haul I,—in 14 fathoms of water: from II-20 a.m. to 3 p.m. 
Wt. 
One Psettodes erumet ae e294 | ak 
A few ‘“‘soles’’ (Cymoglossus ‘macrolepido- 
tus) é ai ati ahs 
Prawns (Peneus spp. ) tage ee 
Arius spp., chiefly dussumieri Bat sOL., 
Total weight of catch oe wer 45. Ub: 
Haul II,—in depth of 24 fathoms: from 4-I5 p.m. to II p.m. 
Although the net was torn the catch consisted of — 
