326 Annals of the Carnegie Museum. 



of the mantle of the female in front of the branchial is very slightly 

 lamellate and finely crenulated. It is even less developed than is 

 generally the case in Obovaria. The edge of the mantle is brown all 

 around, often very pale, often darker, and becomes blackish in the 

 region of the branchial and anal. Marsupium generally quite large 

 and swollen, with as many as forty ovisacs, or even more. At its 

 edge there is generally brownish or blackish pigment, but this may be 

 indistinct, or even lacking. For an account of the glochidia see Lea, 

 Obs., VI, 1858, pi. 5, fig. 18; Ortmann, 191 lb, pi. 89, fig. 16. Length 

 0.22; height 0.24. Lefevre and Curtis (1910, pi. 4, figs. 24 and 27) 

 have figured the placenta?, but they are distinguishable only when 

 the eggs are present, later the cohesion is lost. 



Nephronajas perdix (Lea). 



I have received three gravid females from B. Walker. They are 

 from the Cumberland River, Burnside, Pulaski Co., Kentucky. 



This species agrees completely with N. ligamentina, and with 

 Obovaria in general. In this species also the inner edge of the mantle 

 of the female in front of the branchial is slightly lamellar and indis- 

 tinctly crenulated, and emphasized by a streak of black pigment. 

 Glochidia rather large. Length 0.25; height 0.29 mm. (see Plate 

 XIX, fig. 12). 



The affinity of this species with N. ligamentina has been recognized 

 by Lea and Simpson, and thus it is not astonishing that the anatomy 

 should prove to be the same. 



Nephronajas sapotalensis (Lea). 45 



Three males, and two sterile females, from Hueyapam River, 

 Hacienda de Cuatotalapam, Canton Alayucan, State of Vera Cruz, 

 Mexico, taken July 23, 1910, have been examined. I received these 

 specimens from A. G. Ruthven, and they belong to the Museum of 

 the University of Michigan at Ann Arbor. One female has been 

 kindly deposited in the Carnegie Museum. 



4b B. Walker writes to me about these specimens: they "agree exactly with Crosse 

 and Fischer's figure of their compidatus, which according to von Martens is probably 

 only a variety of sapotalensis, differing mainly in having the pseudocardinals slender, 

 while in sapotalensis they are heavy." The type locality of sapotalensis is Sapotal 

 River, near Tlocatalpam, Mexico. This is not far from the locality of my speci. 

 mens, and in the same general drainage system (Papaloapan and San Juan Rivers)- 



