IIl8 PARRKYSIA 



Margaron (Unio) rajahcnsis Lka, Syn., 1852, p. 25; 1870, p, 



38. 

 Parrcysia rajahcnsis Simpson, Syn., 1900, p. 844. 

 Unio indicus Sowkrp.v, Conch. Icon., XVI, 1866, pi. xl, fig. 



222. — Hanley and Ttieobaui, Conch. Ind., 1876, p. 43, pi. 



CLII, fig. I. 

 Margaron (Unio) indicus Lka, Syn., 1870, p. 31. 



I have only seen the type, but it seems to me that the species 

 is very distinct. I'he almost angular posterior ridge with the 

 rather deep radial groove above it are excellent distinguishing 

 characters. 



Group of Parrcysia ritgosa. 



vShell rather solid, elliptical to subtrapezoidal ; beaks full,, 

 with zigzag-radial sculpture and fine corrugations and gran- 

 ules over the surface of the shell. 



Parreysia rugosa (Gmelin). 



Shell long elliptical or long rhomboid, subinflated, rather 

 solid, inequilateral ; beaks full and high, with strong, zigzag- 

 radial sculpture ; posterior ridge rounded ; anterior end round- 

 ed, sometimes angled above ; base line nearly straight ; pos- 

 terior end rounded or obliquely subtruncate above ; dorsal out- 

 line arcuate ; surface with irregular growth lines ; epidermis 

 greenish in young shells, brownish in old ones ; pseudocardi- 

 nals solid, much split ; laterals straight, two in the left valve 

 and a partly double one in the right ; anterior scars deep ; pos- 

 terior scars shallow ; nacre salmon, iridescent, thicker in front.. 



Length of type 42, height 24 mm. 



Length of shell in Lea collection 57, height 34, diam. 22 mm. 



Coromandcl. 

 Mya rugosa Gmelin, Syst. Nat., 13th ed., 1788, p. 3222. — 



Wood, Ind. Test., 1825, p. 12, pi. n, fig. T,T,a\ rev. ed., 1856, 



p. 16, pi. II, fig. 33. 

 Unio rngosKs Kustkr, Conch. Cab. l^nio, 1862, p. 290, pi. 



xcvii, fig. 5. 

 Parrcysia rugosa .Simpson, Syn., 1900, p. 844. 



Gmelin refers to the Mya corrugata magna, etc., of Chemnitz 

 in the tenth volume of the Conchvlien Cabinet, p. 346, pi ci.xx,. 



