174 UNiONiD.i:. 



small, very deeply excavated; posterior scars also small, ovate, 

 deeply impressed ; interior of shell whitish iridescent. 



Long. 29, lat. 41, diam. 20 mm. 



Hah. Gowhatty. 



The type specimen is in the Indian Museum. 



309. Parreysia (Parreysia) dalliana, Frierson. 



Parreysia [Parreysia) dalliana, Frierson, ' Nautilus,' Boston Mass. 

 xxvi, p. 142; Haas, Martini & Chemnitz, Conch. -Cab. pi. 32, 

 figs. 3, 4 (as Trapezoideusfoliaceus). 



Original description : — Shell small, rather thick, somewhat 



ovate Rounded before, basal and dorsal lines nearly 



straight, post basal point rounded. Epidermis olivaceous, 

 greenish in young shells, brownish in old specimens, and 

 frequently hJeached. Beaks \GYy small, pointed, low, and in- 

 curved, with fine zigzag radial sculpture, which extends a little 

 down the shell, and especially dov.'n the post slope : in dirty or 

 eroded specimens hardly to be noticed. The shell is a little 

 intlated, the post ridge rounded. Inside the nacre is soft cream 

 or white. The left valve has two cardinals, the anterior blade- 

 like, and the posterior much smaller and tubercular. The laterals 

 are double (or even inclined to be trifid) ; in the right valve the 

 cardinals are split or double, and the laterals single. The 

 anterior cicatrices are confluent, and also those of the posterior. 



Long. 25, lat. 40 mm. 



Hah. Burma. 



" The shell is stouter, shorter, and more inflated than 

 T. foJiaccus, and the postei'ior portion is not green.'' 



Genus LAMELLIDENS. 



Lumellideiis, Simpson, Washington. D.C., Smiths. Inst., Nat. Mus. 

 Proc. xxii, 1900, p. 854. 



Type, Unio marginaJIs, Lamarck, from India, Burma, and 

 Ceylon. 



Range. India; Burma; Ceylon and China. 



Original description : — Shell elongate, elliptical, pointed behind, 

 with a slight post-dorsal wing, a low, often biangulate posterior 

 ridge, and genei'ally t\^ o sharp, radiating lirae above it ; beaks with 

 curved, radiating ridges which sometimes are slightly zigzag and 

 often become almost concenti-ic, but which fade out as they approach 

 each other at the centre of the disc ; epidermis smooth, generally 

 shining, brownish, often with concentric bands of lighter colour, 

 rayless or nearly so ; left valve with two compressed pseudo- 

 cardinals, the front one roughened, and two laterals ; right valve 



