1 234 DIPLODON 



with whicli they were, no doubt, once clothed. It is nearly 

 allied to parai:!_uaycnsis herein described, but differs much in 

 the elliptical outline." 



Yur. bocttgeri (von Ihering). 



">Shel] lower, with the posterior end subrostrate and angu- 

 lated." (von Ihering). 



San Paulo, Brazil. 

 Unio iirmiis I^ea var. bcrttgcri von Ihering, Arch, fiir Nat., 



1893. p. 105. pi. IV, fig. II. 

 Diplodon finr.ns var. bccitgcri Simpson, Syn., 1900, p. 874. 



DiPLODON URUGUAYENSis (Lea). 



Shell subrhomboid, somewhat inequilateral, with full but 

 not high beaks ; posterior ridge full and rounded, ending be- 

 hind in a rounded point near the base of the shell ; posterior 

 slope hollowed out ; surface finely, concentrically sculptured ; 

 epidermis greenish and brownish, somewhat banded, the hind- 

 er half of the shell darker; left valve with one compressed, 

 ven,' rough pseudocardinal and two straight laterals ; right 

 valve W'ith two compressed pseudocardinals, the upper small, 

 and one lateral ; anterior muscle scars small, impressed ; nacre 

 white, tinted blue, thicker in front. 



Length 70, height 45, diam. 30 mm. 



Uruguay River, South America. 

 Unio nriiguayensis I^ea, Pr. Ac. N. Sci. Phila., IV, i860, p. 



90; Jl. Ac. N. Sci. Phila., V, 1863. p. 388, pi. xlv. fig. 298; 



Obs., X, 1863, P- 24, pi. XLV, fig. 298. — SowERBY, Conch. 



Icon., XVI, 1868, pi. i.xxxiv, fig. 448. 

 Margaron (Unio) uruguayensis Lea, Syn., 1870, p. 46. 

 Diplodon uruguayensis Simpson, Syn., 1900, p. 875. 



Y&ry close to D. wymanii and possibly only the young of 

 that. It differs in having the peculiar dark posterior end, the 

 coloring of which seems to be a very wide, feeble ray, and in 

 the teeth. The pseudocardinals of D. zvymanii are subradial 

 and much split, those of this species are compressed and not 

 split : the laterals of wymanii are curved and granular, those 

 of unigitavrnsis are straight and nearlv smooth. 



