316 Annals of the Carnegie Museum. 



generally more or less injured. 39 Anal large, with crenulations. 

 Branchial large, with papillae; toward the front papillae gradually 

 changing to crenulations, which soon disappear, so that the anterior 

 inner edge of the mantle is smooth. Palpi of usual shape, but small; 

 their posterior margins united for about one-half, or less, of their 

 length. 



Gills conforming to the shape of the shell, rather short and broad, 

 the inner much the wider anteriorly. The anterior attachment of 

 the gills is as usual. Gill-diaphragm normal. Inner lamina of inner 

 gills free from abdominal sac, except anteriorly, where it is connected for 

 about one-third to almost one-half of the length of the abdominal sac. 



\an 



\br 



mp 



Fig. i 8a. Gravid female, medium size (shell 55 mm. long), from Cumberland 

 River, Eadsville, Wayne Co., Ky. (Cam. Mus., No. 61, 4,968.) 



Gills with'welldeveloped water-tubes and septa. Those of the male, 

 and the non-marsupial gills of the female, with distant septa and wide 

 water-tubes. Marsupium formed by the posterior section of the outer 

 gill; more than'half of the gill takes part in it; a larger section in 

 front and a smaller behind remain non-marsupial. The marsupial 

 part bulges outYconsiderably beyond the original edge of the gill, 

 about as wide again as the gill, and in this section the septa are much 

 more crowded, and the ovisacs are narrow. When gravid, the ovisacs 

 swell only slight ly.Jso that they are very little compressed, and chiefly 

 so near their base. The placentae have the same subcylindrical and 

 only slightlyfcompressed shape. Practically the whole of each ovisac 



39 But in some it/was positively absent. This is also a rather primitive condition, 

 not observed in'any other form of the Lampsilince. 



