﻿30 TRUNCILLA 



Unio capsccformis Lea. 'Pr. Am. Phil. Soc, VI, 1834, p. 31, pi. 

 II, fig. 4; — Obs., I, p. 143, pi. II, fig. 4. — Conrad, Monog., 

 VIII, 1837, J), yi, pi. XL, fig. 2, 3. — Hanlky, Biv. Shells, 

 1843, P- i9> pl- '^^^> fig- 5- — KusTER, Conch. Cab. Unio, 1852, 

 p. 44, pi. viii, fig. 5. — Rrkve, Conch. Icon., XVI, 1864, pi. 

 XVII, figs. 79, 790, yc)b. 

 Margarita (Unio) capsccformis Lea, v^yn., 1836. p. 24; 1838, 



p. 19. 

 Margaron (Unio) capsccformis Le\, Syn., 1852, p. 2y ; 1870, 



p. 42. 

 Trnn cilia capsccformis Simpson, Syn., looo. p. 524. 



The above measurements of a male sliell are from a rather 

 large specimen. I have seen female shells considerably larger 

 than the specimens whose measurements I have given, but they 

 do not often grow larger. The species is less solid than most 

 of the members of the group, the male shell being nearly evenly 

 elliptical and that of the female having a greatly rounded, com- 

 pressed marsupial swelling. It resembles the female of T. per- 

 ple.ra, but is smaller, thinner, is less rude and lacks knobs. 



TrUNCILLA FLORENTINA (Lea). 



Shell irregularly elliptical or obovate, more or less inflated, 

 inequilateral, rather solid ; beaks quite full and elevated ; sur- 

 face with uneven growth lines ; epidermis yellowish-green, 

 feebly rayed; pseudocardinals small, triangular, double in each 

 valve ; laterals double in the left valve, single or partly double 

 in the right ; anterior scars small, impressed ; posterior scars 

 shallow ; nacre bluish-white, thicker in front. Male shell irreg- 

 ularly elliptical, with a decidedly double posterior ridge, which 

 ends in a biangulation behind, with a shallow radial depression 

 in front of it, the ridge in front of this full ; female shell with 

 a somewhat produced, rounded, thin, compressed marsupial 

 swelling, usually not darker than the rest of the shell, often 

 toothed and marked off from the rest of the shell by sulci. 



Length (male) 44, height 32, diam. 23 mm. 



Length (female) 33, height 26, diam. 18 mm. 



Tennessee River drainage. Cumberland River. 



Type locality, Florence. Ala., and Cumberland River, Tenn. 



