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, pl. 5, fig. 18; Ortmann, 19110, pl. 89, fig. 16. Length 
0.22; height 0.24. Lefevre and Curtis (1910, pl. 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 NN. 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 
XG hig. 2): 
The affinity of this species with JN. 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).” 
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. 
4 B. Walker writes to me about these specimens: they ‘‘agree exactly with Crosse 
and Fischer’s figure of their computatus, 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) - 
