40 THE NAUTILUS. 



leaving a small posterior part of the gill non-marsupial. There 

 are about 12 ovisacs on each side in my gravid female. 



In the female, the mantle margin in front of the branchial 

 opening has the inner edge nearly parallel to the outer. The 

 outer edge is denticulate posteriorly (corresponding to the den- 

 ticulate margin of the shell). The inner edge has, just in front 

 of the branchial, a few small papillae, and then it is lamellate 

 and elevated, and rather smooth. Farther in front, there are 

 again a few small papillae. This differentiated part of the inner 

 edge reaches nearly to the middle of the lower margin. The 

 lamellar elevation is very distinct, and sharply defined from 

 the anterior and posterior papillate part, and is slightly longer 

 than either of them, and, in the specimen at hand, somewhat 

 thickened, with a blunt edge (of course, the specimen is con- 

 tracted by the action of the alcohol; it is probable that this 

 edge was capable of some sort of expansion ) . In the region of 

 the lamella, the inner edge of the mantle is farthest remote from 

 the outer, but not much so, and there is no sudden drawing 

 apart of the mantle edges (as in the genus Truncilla). 



In the male, the female structure of the inner mantle is indi- 

 cated in a rudimentary condition: the papillae are extremely 

 small, and the smooth lamellar part is present, but thin and 

 hardly elevated. 



Color of the soft parts whitish. Edges of mantle brownish, 

 blackish in the region of the anal and branchial, and the outer 

 edge is spotted black and brown in this region, chiefly in the 

 female. A black streak runs along the inside of the inner edge 

 in front of the branchial, extending, in the female, upon the 

 lamellar elevation, which is entirely black. Edge of marsupium 

 pale (without black pigment). 



Glochidia subovate, higher than long. L. 0.21, H. 0.26 mm. 



The genus Lemiox is a Lampsiline form with very peculiar 

 shell characters, the most remarkable of which is the sculpture 

 of the posterior part of the shell by rugose wrinkles, which pro- 

 duce, in the female, a distinctly, but irregularly, denticulate or 

 scalloped margin of the shell. The postbasal expansion of the 

 female shell is rather small, but distinct, and corresponds, in 

 its location, to the lamellar expansion of the inner mantle edge. 



