I26o DIPLODON 



moderate, rounded or faintly double ; beaks raised a little above 

 the dorsal line, moderately full, sculptured with a few, widely 

 spaced, narrow, short, radial bars, the central pair coalescing; 

 surface wath fine, concentric sculpture, becoming much strong- 

 er on the later growth ; epidermis bronzy-olive in front, rich 

 bronzy-brown behind ; left valve with a sort of double, com- 

 pressed, rough pseudocardinal and two curved laterals ; right 

 valve with two compressed pseudocardinals, the upper small, 

 and one lateral ; muscle scars impressed ; nacre bluish-white, 

 lurid purplish in the cavities, slightly thicker in front. 



Length 67, height 34, diam. 21 mm. 



Island of Chiloe, Chile. 



Unio aplatiis Rkeve, Conch. Icon., XVI, 1865, P^- xxviii, fig. 



H3- 

 Diplodon a plains Simpson, Syn., 1900, p. 881. 



A little larger, more inflated, and more bronzy than D. 

 gassie.':!. I.ea has a shell from Cuming, which agrees very 

 closely with Reeve's figure of aplatus. The nacre is not quite 

 so much thickened in front as is that of gassiesi. 



DiPi.ODON :\i()i.iN.7i (Philippi). 



Shell long rhomboid, the dorsal and ventral lines parallel , 

 subcompressed, inecjuilateral, subsolid ; beaks low with short, 

 radial bars ; epidermis pale yellowish-brown or greenish-brown 

 on the front half of the shell, rather suddenly becoming dark 

 green on the posterior half ; there are sometimes a few, scat- 

 tered rays on the anterior part ; teeth compressed ; nacre bluish- 

 white. 



Length 67, height 40, diam. 21 mm. 



Southern Chile. 

 Unio molincc Phiijppi, Conch., Ill, 1847, p. 50, pi. iv, fig. 4. — 



KusTKR, Conch. Cab. Unio, 1862, p. 281, pi. xcv, fig. i. 

 Diplodon violincc Simpson. Syn.. i(}oo, p. 881. 

 Unio auratiis Sowkrrv. Conch. Icon., X\'T, 1866, pi. xlv, fig. 



245- 



The almost exactly rhomboid form and the peculiar pattern 



of color would seem to be pretty good characters by which 



