NO. 1205. SYNOPSIS OF THE NAIADES SIMPSON. 



tOBOVARIA LENS var. DEPYGIS Conrad. 



* Unio depygis CONRAD, Am. Jl. Conch., II, 1866, p. 107, pi. x, fig. 1. B. H. WRIGHT, 



Check List, 1888. 



Ohio Kiver drainage; southern Michigan. 



tOBOVARIA UNICOLOR Lea.' 



* Unio unicolor LEA, Tr. Am. Phil. Soc., IV, 1845, p. 163; * Tr. Am. Phil. Soc., IX^ 



1848, p. 74, pi. iv, fig. 12; * Obs., IV, 1848, p. 48, pi. iv, fig. 12. * CONRAD 

 Pr. Ac. N. Sci. Phila.,VI, 1853, p. 259. *H. ami A. ADAMS, Gen. Rec. Moll., 



II, 1857, p. 492.* B. H. WRIGHT, Check List, 1888.* P^TEL, Conch. Sam., 



III, 1890, p. 171. 



*Margaron ( Unio} unicolor LEA, Syn., 1852, p. 34; 1870, p. 55. 



Mississippi and Alabama, in streams flowing into the Gulf. 

 tOBOVARIA LEIBII Lea. 2 



*Unio ItiUi LEA, Proc. Acad. Nat. Sci. Phila., VI, 1862, p. 168; * Jl. Ac. N. Sci. 

 Phila., VI, 1866, p. 44, pi. xv, fig. 42; Obs., XI, 1867, p. 48, pi. xv, fig. 42* B. H. 

 WRIGHT, Check List, 1888. 



* Margaron ( Unio) leibii LEA, Syn., 1870, p. 36. 



Lake Erie and streams falling into it; southern Michigan ; ?Sequatchie 

 Eiver, Tennessee. 



tOBOVARIA ROTULATA B. H.Wright. 



* Unio rotulatus B. H. WRIGHT, Naut., XIII, 1899, p. 22. 



* Obovaria rotulata SIMPSON, Pr. Ac. N. Sci. Phila., 1900, p. 78, pi. iv, fig. 2. 



Eocambia River, Escambia County, Florida. 



Subgenus PSEUDOO'N Simpson, 1900. 

 (Type, Unio ellipsis Lea.) 



Shell elliptical, inflated, solid, that of the males slightly pointed at 

 the upper posterior part ; epidermis brownish or blackish, ray less or 

 very feebly rayed, beaks anterior; pseudocardinals solid, stumpy, or 

 slightly elongate in age, and showing a tendency toward being parallel 

 with the laterals; cicatrices deep; nacre silvery, iridescent posteriorly. 



Animal with mantle having a wide, thickened, double border, the 

 inner edge being toothed throughout below; gills small; marsupium 

 not reaching to the posterior end of the outer branchia;, though extend- 

 ing quite well forward; ovisacs rather numerous, large and distinct, 

 tinted with purple below; anal and branchial openings finely toothed. 



*The type is a young female, somewhat broken, and besides this Lea has a shell 

 which he has so named that I believe is O. castaneus. Under the name of Unio lens 

 (Cat. No. 85743, U.S.N.M.) he has a young shell from Jackson, Mississippi, which is 

 a young male unicolor. The species grows to the size of 0. lens, but shows dull rays 

 and is more inflated than that species. 



2 Dr. Lea states that the type is from Erie County, Michigan. There is no county 

 of that name in the State, and his specimens may be from Erie County, Ohio. I am 

 very doubtful whether it is more than a dwarf variety of U. drculus, as specimens have 

 been seen from Tennessee which seem to stand between the two forms. 



