NO.1205. SYNOPSIS OF THE NAIADES— SIMPSON. 753 



\*Unio crebrivittahis Lea, Pr. Ac. N. Sci. Phila., VI, 1861, p. 60; *J1. Ac. N. Sci. 

 Phila., VI, 1866, p. 43, pi. xv, fig. 41; *0b8., XI, 1867, p. 47, pi. xv, fig. 41.— 

 *B. H.Wright, Check List, 1888. 



* Margaron ( Unio) crebrivittatus Lea, Syn., 1870, p. 40. 



*?Unio medins Reeve, Conch. Icon., XVI, 1864, pi. xvii, fig. 77. 



Alabama and Tombigbee river systems. 



fPLEUROBEMA CHATTANOOGAENSIS Lea. 



"* Unio chattaiioogaensis Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 166; * Jl. Ac. N. Sci. 

 Phila., IV, 1859, p. 209, pi. xxv, fig. 90; *^ Obs., VII, 1859, p. 27, pi. xxv, fig. 

 90.— * Reeve, Conch. Icon., XVI, 1864, pi. xvi, fig. 69.— B. H. Wright, Check 

 List, 1888.— *P^TEL, Conch. Sam., Ill, 1890, p. 148. 



* Margaron {Unio) ehattanoogaensis Lea, Syn., 1870, p. 40.' 



Alabama Eiver system. 



tPLEUROBEMA INTERVENTUS Lea. 



* Unio interventus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60; * Jl. Ac. N. Sci. 



Phila., V, 1862, p. 84, pi. xi, fig. 233; * Obs., VIII, 1862, p. 88, pi. xi, fig. 233.— 



* B. H. Wright, Check List, 1888.—* P^etel, Conch. Sam., Ill, 1890, p. 156. 

 ^Margaron ( Unio) interventus Lea, Syn., 1879, p. 40. 

 t*Z7wio palUdofulvus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60; * Jl. Ac. N. Sci. 



Phila., V, 1862, p. 83, pi. xi, fig. 332 ; * Obs., VIII, 1862, p. 87, pi. xi, fig. 232.— 



*B. H. Wright, Check List, 1888. 

 *Margaron ( Unio) pallidofulvus Lea, Syn., 1870, p. 40. 



Cahawba Eiver, Alabama. 



fPLEUROBEMA MURRAYENSIS Lea. 



""Unio murrayensis Lea, Pr. Ac. N. Sci. Phila., II, 1868, p. 143; *J1. Ac. N. Sci. 

 Phila., VL 1869, p. 303, pi. xlvi, fig. 115; *0b8., XII, 1869, p. 62, pi. xlvi, 

 fig. 115.— *B. H. Wright, Check List, 1888. 



* Margaron ( Unio) murrayensis Lea, Syn., 1870, p. 40. 



Coosa Eiver system ; Columbus, Georgia ? 



(Group of Pleurohema curta.) 



Shell elongate triangular, truncated in front, rounded on the base 

 where it is quite full behind the middle, with a low posterior ridge, the 

 space between the middle of the disk and the ridge flattened or some- 

 times slightly excavated, rather sharply pointed behind; umbonal 

 region very prominent; beaks well forward; beak sculpture not ob- 

 served; epidermis rather smooth, brownish olive; pseudocardinals dis- 

 tinct, triangular, radiate; laterals heavy, slightly curved; cicatrices 

 small and deep; nacre iridescent posteriorly. Aniimil with the gills 

 large, semicircular, the outer slightly larger than the inner, which are 

 free nearly their whole length from the abdominal sac; marsuijinm 

 occupying the entire length of the outer gills. 



' Probably did not come from Chattanooga, Tennessee, as Dr. Lea believes, but 

 from some of the streams of northern Georgia or Alabama, which drain southward. 

 According to Hon. T. H. Aldricli, the animal of this and allied species is a brilliant 

 scarlet. 



Proc. JST. M. vol. xxii 48 



