90 Dwellers of the Sea and Shore 



bers of the suborder Macriira, the lobster and the well- 

 known fresh-water crayfish can be cited as the most 

 familiar types. The distinguishing feature that places 

 them in this division is, as the name implies, the pos- 

 session of a long cylindrical abdomen, or hind body. 



To the Brachyiira only, belong the true crabs. And 

 these are distinguished by the inconspicuous flat hind 

 body reflexed along the under side of the thorax, or 

 fore body. A common example of this division is the 

 edible, or blue, crab of our tables. 



These distinctions, by the way, are not arbitrary 

 arrangements made merely to suit the convenience of 

 the systematic scientists; for the most superficial ac- 

 quaintance with comparative anatomy soon reveals that 

 the crablike animal differs more greatly from the 

 lobsterlike individual than does the dog from the cat. 

 It is therefore because of this anatomical, or, to use a 

 more correct term, this morphological difference that 

 the hermit crab is incontestably removed from the 

 brachyurians, or crabs. 



However, regardless of those general features of his 

 hind body that cause him to be set apart from the crabs, 

 he is by reason of a striking modification of the form 

 and function of this part of his anatomy peculiarly dis- 

 tinguished from all other creatures of his kind. Indeed, 

 it is on this account that some writers have relegated 

 him to a distinct group of his own, known by the name 

 of Ano7nura, the "nameless bellied"; for his unusual 

 hind body not only makes him notorious among crus- 

 taceans but places him among the curiosities of nature. 



Unlike the fore body and its appendages, which are 

 armored with a hard, tough crust, the abdominal region 



