﻿MKDIONIDUS 251 



at the base of the shell ; in the female shell, which is smaller, 

 the posterior point is considerably elevated above' the base and 

 the marsupial area is decidedly swollen. 



Length (male) 45, height 23, diam. 16 mm. 



Length (female) 36, height 18, diam. 15 mm. 



Type locality, branch of Flint River, Baker County, Georgia. 

 Unio kingi B. H. Wright, Nautilus, XH, 1900, p. 139. 

 Medionidus kingi Simpson, Syn., 1900, p. 590. 



This species is more solid than any member of the group. 

 It is considerably inflated, and has a more tawny epidermis 

 than any of the others. 



Medionidus acutissimus (Lea). 



Shell small, subinflated, rhomboid, with a high, sharp, some- 

 times slightly double posterior ridge ; beaks rather prominent, 

 their sculpture not observed ; posterior slope and sometimes 

 the greater part of the shell corrugately folded ; surface shin- 

 ing, yellowish or greenish, marked with faint rays composed 

 of zigzag or broken lines ; left valve with two stumpy pseudo- 

 cardinals and two laterals ; right valve with one pseudocardinal 

 and one lateral, nacre salmon, flesh-color or whitish, pur- 

 ple or reddish. Male shell arcuate, the hinder end drawn 

 down to a sharp point at the posterior base ; in the female 

 shell this point is elevated a little above the base line and the 

 middle of the base is swollen. 



Length (male) 45, height 20. diam. 18 mm. 



Length (female) 35, height 17, diam. 13 mm. 



Alabama River systemi. 



Type locality, Alabama River. 

 Unio acutissimus Lea, Tr. Am. Phil. Soc, TV. 183 1. p. Sq. pi. 



X, fig. 18 ; Obs., I, 1834, p. 99, pi. X, fig. 18. — Conrad, Mon- 



og., X, 1838, p. 86, pi. XLVii, fig. 2. — Hanlky, Biv. Shells, 



1843, p. 177, pi. XXII, fig. 35.— Ciienu, 111. Conch., 1858, pi. 



VIII, figs. 3, 3a, 3&. — SowERBY, Conch. Icon., XVI, 1866, pi. 



XXXVI, i]g. 189. 

 Margarita (Unio) acutissimus Lea, Syn., 1836. p. 14; 1838. 



p. 14. 



