>ODL'L.\.niA. 141 



tooth also on the margin, at the base of which appears a second 

 and much smaller tooth ; posterior lateral gently curved, narrow, 

 sharp, falling between two equal sized lamelhc in the left valve ; 

 anterior muscular scar moderately to slightly deep, posterior 

 muscular scar superficial. 



Long. 27, lat. 47*25 mm. 



Ilah. Eivers of India ; Pegu (Ind. Mus. Coll.). 



The species seems to vary greatly in shape and colour, some 

 specimens, in the long series of the Indian Museum Collection, 

 being posteriorly much more rosti-ate than other.s, while in some 

 the dorsal margin is angled posteriorly and produced anteriorly. 

 In colour the species seems to vary from pale yellowish green to 

 dark blackish brown, and thus two extremes might easily be 

 taken at first sight for different species : there does not seem, 

 however, to be any clear line of demarcation between the many 

 varieties, all of which merge into one another when a sufficiently 

 large series is examined. 



273. Nodularia (^Nodularia) pugio {Benson). 



Nodularia {Xoduktvia) puyio (Beuson) ; Simpson, ^\'ashiugtoii, D.C., 

 Smiths. Iu3t., Nat. Mus. Proc. xxii. 1900, p. 814. 



Unio piK/io, Benson, A. M. N. 11. x, 186i', p. 193 ; Sowerby, Conch. 

 Icon. pi. 45, tig-. 516 ; H. & T., C. I. 1876, p. 5, pi. 10, tig. 7. 



Original descvijition: — Testa transverse elongato-triangulari, 

 liuguseformi, valde insequilaterali, compressiuseula, crassa, antice 

 brevissima, subito desceudente rotundata, postice sensim angus- 

 tiore, cuneiform i, demum acuminata, margine dorsali recta, 

 ventrali convexiusculo, postice ascendente ; umbonibus late 

 planatis, la;vibus, prominentibus, carina umbonali subito obtuse 

 angulata, area interjacente versus cardinem descendente ; disco 

 subplauulato, laniusculo, substriato ; dente cardinal! (valvte 

 dextroD)brevi, crassa prominente, radiato-sulcata, laterali elongata, 

 subduplicata, iutus crenulata : margarita albida, iridescente. 



Long. 21, lat. 42, diam. 16 mm. 



Hah. !XeighbourhooJ of Ava, Pegu (Indian Mus, Coll.) ; also 

 recorded from the Barrack Kiver, Silehar. 



A curious species whose smooth surface and anteriorly swollen 

 and posteriorly cuneiform shape easily distinguish it from any 

 other Indian members of the family. 



274. Nodularia (Nodularia) gratiosa {Pldlippi). 



Kodulavia {Nodiilariu) f/ratiosa (Philippi) ; Simpsou, Washington, 

 B.C., Smiths. Inst., Nat Mus. I'roc. xxii, 1900, p. 815. 



Unio f/ratiosus, Philippi, Conch, i. 1845. p. 20, pi. J, tig. 5 ; Catlow 

 & lleeve, Conch. Noni.1845, p. 59; ? Kiister, Conch. Cab., Unio, 

 18Gl,p. 239, pi. 80, fig. 3. 



Maryuron {Unio) yrutiosus, Lea, Syn. 1870, p. 32. 



