gradually to a point. As in the case of the male, 

 this portion of her reflexed hindbody lies in a de- 

 pression underneath, fitting so snugly that it forms 

 an even surface with that of the forebody. As I 

 have previously indicated, the claws of the female 

 are smaller than those of the male; but as these 

 are sometimes missing, and often of variable size 

 even in the males (owing to regeneration), the 

 shape and width of the abdomen offer a ready 

 means by which to distinguish an individual's sex. 



My series of molts tells me something else; it 

 tells me that the tapering form of the young fe- 

 male's abdomen persists throughout her successive 

 sloughing until her adult form is reached, where- 

 upon it becomes a broad semicircular expanse, a 

 great apron almost completely covering the region 

 that lies posterior to the mouth. It is also consider- 

 ably thickened; no longer lying flush within the 

 depression of the forebody, its surface is elevated, 

 conspicuous, and its border is fringed with hairs. 



And here, it should be added, is another curious 

 change: the abdomen previous to its last form is 

 bare and, except for the transverse lines marking 

 the constrictions between the segments, smooth as 

 ivory; after the final molt it bears, like the crab's 



[262] 



