ORTMANN: FAMILIES AND GENERA OF NAJADES. 293 
Color whitish. Foot orange-yellow, palpi and gills brown. Edge 
of mantle brown, black behind. Charged marsupium yellowish white 
(with eggs) to liver-brown (with glochidia).22 The orange tint of 
the foot is variable, lighter or darker. 
Anodonta cataracta Say. 
About twenty-five specimens from various places in the Atlantic 
drainage of eastern Pennsylvania have been investigated. 
The breeding season begins in August, in which month I repeatedly 
found gravid females with eggs. I have no other observations of 
my own, but Conner (1907, p. 88) gives October to May as the breeding 
season. 
Lea (Obs., II, 1838, pl. 15, fig. 46) has figured the animal, but his 
figure is practically useless. 
The soft parts resemble in every respect those of A. grandis. I have 
seen the glochidia of specimens from the Delaware River, collected 
by C. H. Conner on March 19, 1911, and they agree with the figure 
published by Lefevre and Curtis (1910, p. 97, fig. C); the dimensions 
are: length 0.36; height 0.37 (identical with those of the glochidia of 
A. grandis). The colors of the soft parts are also the same. 
I have my doubts as to the specific distinctness of this form from 
A. grandis. At any rate, it is merely the eastern representative of the 
western grandis, and does not have any close affinity to the European 
species and the Anodontas of the Pacific slope of America, as Walker 
(1910a, p. 135) believes, and there is no reason to think that ‘it was 
a co-immigrant with Margaritana margaritifera to the east coast of 
North America” (from Europe). A. cataracta is, if anything, an east- 
ern offshoot of the A. grandis-stock of the central basin. 
Genus ANODONTOIDES Simpson. (1898.) 
(Simpson, 19008, p. 658.) 
Shell subelliptical, thin, inflated, with smooth disk. Beak-sculpture 
distinct, but not very heavy, consisting of concentric ridges curved 
up behind, not double-looped. Hinge-teeth absent, or represented 
by the merest rudiments. 
Soft parts much like those of Anodonta. Outer gills alone marsupial, 
when charged distending at the edges, and secondary water-tubes 
present, ovisacs not subdivided. No placente developed. Inner 
22 Sometimes the light color is preserved in the glochidial-stage. 
