350 



Annals of the Carnegie Museum. 



apparently indicates the over-lapping of the seasons in this species 

 also. 



The description of the soft parts given by Lea (Obs., XIII, 1874, 

 p. 72) is very incomplete. But judging from the specimens before me 

 they are absolutely identical with those of L. luteola. Glochidia: 

 length 0.21; height 0.27 mm. (see Plate XX, fig. 10). 



Lampsilis ovata (Say). 



The soft parts of about half a dozen specimens have been preserved, 

 but many more have been examined in the field. They were all from 

 the Ohio drainage in Pennsylvania. 



Gravid females have been found in August, September, and October. 



Lea (Obs., X, 1863, p. 435) describes the soft parts. 



■-? an 



br 



rnp 



Fig. 26. Lampsilis ovata (Say). Gravid female, from Allegheny River, Kelly, 

 Armstrong Co., Pa. (Cam. Mus., No. 61, 2,997.) Coll, Sept. 27,1907. 



The flap in front of the branchial opening is greatly developed. 

 When contracted, it has only a rounded, toothed lobe at the anterior 

 end. But when expanded (see figure of L. ventricosa, Ortmann, 

 1911&, p. 320, fig. 8) it is much longer. The edge of the lamellar 

 expansion is practically smooth, but the free lobe has irregular teeth. 

 An rye-spot is present at the posterior end, but this is indistinct in 

 the contracted condition. Anterior to the free lobe the inner edge of 

 the mantle is slightly crenulated, and then smooth. 



