190 ijxioxiD.i:. 



315. Lamellidens nongyangensis, Preston. 



Lainellidens nmiffi/anensis, Preston, Rec, Ind. Mas., Calcutta, vii, 

 1911^ p. 306. 



Original description : — Shell very elongately ovate, inflated, 

 covered with a hlackish-brown, finely laminiferous periostracum, 

 concentrically marked uith rather coarse lines of growth ; dorsal 

 margin anteriorly somewhat straight, posteriorly arched above, 

 sloping and slightly excavated below ; ventral margin scarcely 

 roimded ; antei'ior side abruptly descending ; posterior side 

 rostrat'e, obtusely rounded; cardinal teeth very anteriorly situate, 

 triangular, erect ; lateral teeth elongate, also erect, tei*minating 

 posteriorlv in an abrupt slope ; anterior scars deeply marked, 

 posterior scars lightly impressed ; interior of shell flesh-coloured, 

 shading to bluish ; iridescent, minutely pitted and granulate. 



Long. 45, lat. 94 mm. 



Bah. Nongyang Lake, South of Patkai. 



The type is in the Indian Museum. 



316. Lamellidens phenchooganjensis, Preston. 



Lamellidens jjlunchoofjanjensis, Preston. Eec. lud. Mus., Calcutta, 

 Vn, 1912, p. 306. 



Original description : — Shell very elongately ovate, posteriorly 

 obtusely rostrate, dark blackish-brown, scidptured with fine con- 

 centric strice, crossed, especially in the anterior median region, by 

 fine, slightly distant, transverse, radiate striae, thus presenting a 

 minutely wrinkled appearance ; umhones 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, some- 

 what fine ; anterior scars ovate, moderately impressed ; posterior 

 scars roughlv 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. 



Bah. Phenchooganj, Central Sylhet. 



The type specimen is in the Indian Museum. 



317. Lamellidens mainwaringi {Kevill, 3IS.),\(Preston.') 



Lamellidens mainicarinrji ( Xevill, MS.), Preston, Rec. Ind. Mus. 

 Calcutta, Tii, 1912, p. 306. 



Orifjinul description : — Shell rather small, cuneate, covered with 

 a finely laminiferous periostracum ; both valves marked with 

 rather fine, concentric, and finer transverse, radiate, scratch-Uke 



