306 Records of the Indian Museum. [ Vor. Voir 
Long. 35, lat. 84 mm. 
Hab.—Narainpore Bhil, Murshidabad District, Bengal (C. J. 
Robertson Milne), Reg. No. *°2° [Type]. 
78. Lamellidens nongyangensis, sp. n. 
Shell very elongately ovate, inflated, covered with a blackish 
brown, finely laminiferous periostracum, concentrically marked 
with rather coarse lines of growth; dorsal margin anteriorly some- 
what straight, posteriorly arched above, sloping and_ slightly 
excavated below ; ventral margin scarcely rounded ; anterior side 
abruptly descending ; posterior side rostrate, obtusely rounded ; 
cardinal teeth very anteriorly situate, triangular, erect ; lateral 
teeth elongate, also erect, terminating posteriorly in an abrupt 
slope ; anterior scars deeply marked ; posterior scars lightly im- 
pressed ; interior of shell flesh-coloured shading to bluish, irides- 
cent, minutely pitted and granulate. 
Long. 45, lat. 94 mm. 
Hab.—Nongyang Lake, South of Patkai, Reg. No. 5048 
[Type]. 
79. Lamellidens phenchooganjensis, sp. n. 
Shell very elongately ovate, posteriorly obtusely rostrate, 
dark blackish brown, sculptured with fine concentric striae, 
crossed, especially in the anterior median region, by fine, slightly 
distant, transverse, radiate striae, thus presenting a minutely 
wrinkled appearance; umbones flattened, much eroded ; dorsal 
margin anteriorly gently sloping, posteriorly more rapidly sloping 
in a slight curve ; ventral margin scarcely rounded ; anterior side 
angled above, gently rounded below; posterior side produced, 
angularly rounded ; hinge teeth very elongate, somewhat fine ; 
anterior scars ovate, moderately impressed; posterior scars 
roughly triangular, not well impressed ; interior of shell shading 
from pale brown to bluish, nacreous, marked, especially towards 
the anterior ventral region, with very shallow radiate furrows. 
Long. 42, lat. 86 mm. 
Hab.—Phenchooganj, Central Sylhet, Reg. No. +88 [Type]. 
80. Lamellidens mainwaringi (Nevill, MS.) sp. n. 
Shell rather small, cuneate, covered with a finely laminiferous 
periostracum ; both valves marked with rather fine, concentric 
and finer, transverse, radiate, scratch-like striae; dorsal margin 
anteriorly gradually sloping, posteriorly arched and more rapidly 
descending ; ventral margin somewhat straight; anterior side 
rounded ; posterior side angled above and below, somewhat obli- 
quely and obtusely rostrate ; hinge-teeth well developed, moder- 
ately short; anterior adductor scar deeply impressed, posterior 
scar somewhat roughly triangular, well impressed ; interior of shell 
bluish iridescent, rather granulate. 
Long. 25°5, lat. 50 mm. 
Hab.—Siliguri, Reg. Nos. #916 [Type], s8s1, 2192; Namtsik, 
Dihang, Reg. No. 5970. 
