Ortmann: Families and Gknkra oi N'aiadks. 353 



hanna ai York Haven, while on August 14, at Selinsgmvc, they were 

 frequent, but had only eggs. Conner's notes (1909, p. 112) are 

 unreliable, lor he has confounded this species with L. ochracea, as I 

 discovered from specimens he sent to me. He gives for ochracea 

 (which would be this species) that it is gravid in April, May, and June 

 My observations are incomplete, but there seems to be an interim at 

 least at the beginning of August. Perhaps the conditions are similar 

 to those in the allied species. 



Lea's figure (Obs., II, 1838. pi. 15, fig. 45) of the soft parts is entirely 

 useless, but the soft parts agree fully with the preceding species. 

 The color is much like L. vaitricosa, but the margin of the mantle and 

 inner side of the flap are generally of a beautiful chestnut tint. Black 

 line on flap sometimes wanting. 



I have only one specimen with glochidia, and even in this they are 

 too young to be correctly measured. But they seem to have the gen- 

 eral shape and size of those of the foregoing species. 



Lampsilis orbiculata (Hildreth). 



Three females, two of them gravid, from the Ohio River in Beaver 

 Co., Pennsylvania, have been examined. 



This species was found gravid with eggs in August (10 and 24), and 

 with glochidia in September, and thus the beginning of the season 

 agrees with that of the other species of this genus. 



Although this species is placed by Simpson close to L. ligamentina, 

 it is not at all related to the latter, which is a Nephronajas, while this 

 is a true Lampsilis, as is shown by the presence of a typical flap (Ort- 

 mann, 1911ft, p. 321). This flap has numerous teeth along its edge, 

 and projects at the anterior end in a free lobe. It also has black 

 pigment on the inside. An eye-spot has not been seen, but this may 

 be obscured on account of the contracted condition of my specimens. 



All the rest of the soft parts are like those of the foregoing species. 

 The glochidia (Ortmann, 191 lb, pi. 89, fig. 22) are peculiar in so far 

 that I have on my slides two sizes of them. The smaller is more fre- 

 quent, length 0.19; height 0.21 mm., and among them are rather rarely 

 larger ones, length 0.20; height 0.25 mm. No intergrades seem to be 

 present. It is not entirely impossible that by some accident in making 

 the slide, the glochidia of another species have become mixed with 

 this one, but this is not very likely. There are no glochidia having 

 the dimensions of the larger ones, except those of L. anodontoides. 



