Ortmann: Families and Genera oi Naiades. 349 



the outer gill, with a very small posterior non-marsupial section. 

 Ovisacs numerous, fifteen to forty, or more. Margin of marsupium 

 with black pigment. Glochidia (Lea, Obs., VI, 1858, pi. 5, fig. 10) 

 rather large, suboval. Length 0.23; height 0.28 mm. 



Color of soft parts whitish, foot more yellowish, gills white to brown- 

 ish. Margin of mantle blackish posteriorly. Color of flap and mar- 

 supium as mentioned above. 



Lampsilis radiata (Gmelin). 



I have not seen more than half a dozen specimens, and among them 

 only one gravid female with eggs, but no glochidia (August 22). 

 They were all from the Susquehanna drainage in Pennsylvania. 



According to Conner (1907, p. 88, and 1909, p. 112) this species 

 breeds "all the year round," but the conditions probably will prove 

 to be the same as in L. lutcola. The beginning of the breeding period 

 is indicated by my specimen. 



The soft parts agree in all essential respects with those of L. lutcola. 

 They have been figured by Lea (Obs., II, 1838, pi. 15, fig. 48 and 49), 

 but fig. 48 does not represent the typical shape of the flap. 



The glochidia have been figured by Lea (Obs., VI, 1858, pi. 5, fig. 20). 



Lampsilis claibornensis (Lea). 



Two males and two gravid females, Pearl River, Jackson, Hinds Co., 

 Mississippi, A. A. Hinkley coll., Nov. 4, 1910. 



Soft parts absolutely identical with those of L. lutcola. Glochidia: 

 length 0.21; height 0.27 mm. 



The glochidia have been figured by Lea as obtusus (Obs., VI, 1858, 

 pi. 5, fig. 1), and as claibornensis (Obs., XIII, 1874, pi. 21, fig. 9). 

 The same author (Obs., X, 1863, p. 406) says of obtusus ( = claiborn- 

 ensis) that it "has large dark papilke below the branchial opening." 

 This is not so in my specimens, which have the typical luleola-flap. 

 Lea's description of claibornensis (ibid., p. 436) is better. 



Lampsilis hydiana (Lea). 



Three gravid females, Bayou Pierre, De Soto Parish, Louisiana. 

 L. S. Frierson coll., August 6, 1910. 



One of these has eggs, indicating the beginning of the breeding 

 season; the other two have glochidia, and one of these has the mar- 

 supium only partly charged, possibly discharged in part. This 



