HIGHER CRUSTACEA OF NEW YORK CITY 



135 



3 THALASSINIDEA 



Moderate sized forms with two longitudinal dorsal sutures and 

 with a cervical suture frequently present. First thoracic legs usually 

 large and chelate. Abdomen large. Burrowing forms. 



Representatives of this group have not so far been taken within 

 the city limits, but species of the genera Callianassa and Gebia may 

 possibly be found. They inhabit deep burrows in the mud or muddy 



Sand ' 4 ANOMURA 



Aberrant forms, at one time placed in a class by themselves but 

 now united with the Macrura. Its principal diagnostic character is 

 ihe reduction of the last pair of thoracic legs and their dorsal posi- 

 tion. It includes the family Hippidae, the sand-bugs, and the 

 Paguridae, the hermit crabs. 



Family hippidae 



Hippa talpoida Say 



Sand-bug 



Hippa talpoida Say, T. Acad. Nat. Sci. Phila. Jour. 1817. 1:160. 

 DeKay. /. c. 1844. p.18, pl.7, fig.17. Verrill. /. c. 1874. P-548, pi. 2, fig. 5. 



An oval and very convex form, 

 with numerous longitudinal stria- 

 tions on the anterior portion of the 

 cephalothorax. Eyes small and on 

 long stalks. Second antennae as 

 long as thorax and fringed with 

 long hairs. First four thoracic legs 

 large, not chelate, and adapted for 

 burrowing. Terminal segment of 

 abdomen long and triangular and 

 folded close under the body. 



The smooth surface and peculiar 

 form of this species render it the 

 most rapid burrower on our shores. 

 It lives in the sand near low 

 water mark, and, if dug out, will rapidly disappear again:, going 

 down into the sand backward. 



Length 25 mm. Color yellowish white tinged with purple. 



Occurs on the exposed southern shore of Long Island. 



Fig. 7 Hippa talpoida (After Verrill) 



