Ortmann; Families and Genera oi Na jades. 346 



and Simpson (in Baker, 1B98, p. 102), and a figure of them has been 

 published by Lefevre and Curtis (1910, pi. 1, fig. 5). 



The inner edge of the mantle of the female in front of the branchial 

 has (see Ortmann, I9II&, p. 318) a row of regular, rather crowded, 

 subequal papillae, which are large and conical, and run forward to 

 about the middle of the ventral margin, where they disappear sud- 

 denly. The anterior part of the inner edge is smooth. The papillae 

 increase somewhat in size from the branchial forward, and the largest 

 papilla' stand near the anterior end of the row. A distinct brownish 

 black streak accompanies this row, and the papillae have the same 

 color at their bases, while they are whitish at their tips. 



Marsupium occupying less than the half of the posterior section of 

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

 sacs fifteen to thirty, without black pigment at their ends. Glochidia 

 (Lea, Obs., VI, 1858, pi. 5, fig. 11 : Lefevre and Curtis, 1910, p. 97, 

 fig. L; Ortmann, 191 lb, pi. 89, fig. 21) as in the preceding species; I 

 have found their length to be 0.22; height 0.28 mm.; while Lefevre 

 and Curtis give length 0.20; height 0.24 mm. 



In other respects like the last species, but inner lamina of inner gills 

 always entirely connected, and mantle-connection between anal 

 and supra-anal shorter than anal. 



Genus Lampsilis Rafinesque. (1820.) 

 (Simpson, 1900b, p. 526 (restricted).) 



Shell ovate to elliptical, or elongated. Outside of shell not sculp- 

 tured. Beak-sculpture of the sinuated or double-looped type, finer 

 or coarser, sometimes the posterior loop open behind, or the sculpture 

 is obsolete. Epidermis generally yellowish or greenish, mostly rayed, 

 often very beautifully so. Female shell quite distinct from that 

 of the male, with a strong inflation and dilatation in the post-basal 

 region, producing a distinct posterior truncation of the shell. 



Inner lamina of inner gills entirely connected with abdominal sac, 

 but sometimes a small hole is left at the posterior end of the foot. 

 In the female, the edge of the mantle in front of the branchial is 

 developed into a ribbon-like flap, generally produced anteriorly into 

 a free, projecting lobe, which has a lacerated appearance. Along the 

 edge of the flap, there may or may not be crenulations or teeth, but 

 never real papillae. On the inside, the flap is beautifully colored, 





