344 



Annals of the Carnegie Museum. 



Eurynia (Eurynia) subrostrata (Say). 

 According to Lea's description (Obs., X, 1863, p. 439, glochidia 

 XIII, 1874, pi. 21, fig. 1, as nashvillensis), and, relying principally 

 upon the figure given by Lefevre and Curtis (1910, pi. 1, fig. 2), 

 this species belongs here. 



Eurynia (Eurynia) recta (Lamarck). 



Numerous specimens from the Ohio drainage and Lake Erie in 

 western Pennsylvania, from Ohio and Arkansas have been investi- 

 gated. 



Bradytictic. The breeding season begins about the middle of 

 August, and ends unusually late, in July (latest date July 23). Speci- 

 mens with fully developed glochidia have repeatedly been found in 



sa 



mp 



Fig. 24. Eurynia (Eurynia) recta (Lamarck). Gravid female, from Lake Erie, 

 Cedar Point, Erie Co., O. (Cam. Mus., No. 61, 4,458.) Coll. August, 1909, by 

 Chas. Brookover. 



July, and for specimens with eggs the earliest date is August 13. 

 Although there is apparently an interim of a few weeks, the seasons 

 come very near to overlapping. But for single individuals there is 

 very likely a longer interval between the breeding seasons, for sterile 

 females are very frequent in August and September, and the majority 

 do not become gravid till October. I cannot detect any difference 

 in this matter in Lake Erie. At any rate, the beginning and end of 

 the breeding season are not later than in the Ohio, in fact the latest 

 date for the end (July 23) is from the Ohio drainage. 



The soft parts have been discussed by Lea (Obs., X, 1863, p. 426) 



