LAMELLIDENS. 181 



Reeve, Concli. Icon, xvi, 1805, pi. 23, fig. Ill : H. & T., C. I. 



1876, p. 19, pi. 41, tig. 1 ; Peetel, Conch. Sam. iii,l890, p. 157. 

 Mar<jaron {Unio) lai/ardii, J^ea, 1870, p. 40. 

 LamelUdens Icnnellatus (Lea), Simpson, Washington, D.C, Smiths. 



Inst., Nat. Mus. Proc. xxii, 1900, p. 8r)6. 



Original description : — Shell siibovate, transverse, somewhat 

 inflated, shining ; valves very thin ; beaks scarcely prominent, 

 undulated ; cardinal teeth long, thin and lamellar ; lateral teeth 

 long, thin, and nearly straight ; nacre bluish. 



Long. 38, lat. 64, diam. 25'5 mm. 



fJab. Bengal {Captain Lang). This variety is represented by 

 specimens in the Indian Museum bearing the following localities : — 

 Mandalay, Pegu, Bliamo {Dr. J. Anderson), also Calcutta and 

 Ceylon. 



Var. sublamellata, Preston, Kec. Ind. Mus., Calcutta, vii, 1912, 

 p. 305. 



Original description : — An elongate, somewhat rostrate form, 

 having the hinge-teeth rather less developed. 

 Hah. Burma ( W. Theobald). 

 The type is in the Indian Museum. 



Subsp. scutum {Sowerhy). 



Unio scutum, Sowerbv, Conch. Icon, xvi, 1868, pi. 94, fig. 510 ; 



H. & T., C. I. 1876,"p. i>2, pi. 46, tig. 1 ; Pastel, Conch, Sam. iii, 



1890, p. 167. 

 Zaniellidens scittum (So-wevhy) , Simpson, Washington, D.C, Smiths. 



Inst., Nat. Mus. Proe. xxii, 1900, p. 8.'J7. 



Original description : — Shell thick, unequally subventricose, 

 somewhat indented in the middle, somewhat depressed in front, 

 very inequilateral, oblong, obliquely sub-biangular behind, of a 

 uniform pitch-colour, smootliish ; ventral edge retuse, rising in 

 front ; umbonal ridge elevated, the space behind it broad and 

 rather concave ; beaks but little projecting, nacre livid whitish ; 

 primary teeth slanting, lateral lamellse distant. 



The dimensions ot the specimen figured in the ' Conch. Icon.', 

 and now in the Ik-itish Museum, are as follows : — 



Long. 50, lat. 100, diam. 32-5 mm. ; 

 and those oF a specimen in the Indian Museum collection : — 



Long. 52-25, lat. 98, diam. 3525 mm. 



Hah. Tenasserim (original locahty); there are also specimens 

 labelled " Rangoon " in the Indian Museum. 



Var. humilior {von Martens), Arch. Naturg. Berlin, Ixv, pt. 1, 

 1899, pp. 45, 4G, pi. 5, fig. 1. 



Somewhat more depressed than the typical form, but agreeing 



