14 NEW-YORK FAUNA — CRUSTACEA. 



GENUS GELASIMUS. Latreille. 



With the general form of the preceding, but broader transversely, and more narrowed behind. 

 Eyes small, rounded, and occupving only the extremities of the peduncles. 



Gelasimus vocans. 



PLATE VI. FIG. 9 & 10. 



Cancer vocans, LiNNEUS, Syst. Nat. 



Ocypode vocans et pvgitator, Bosc, Vol. 1, p. 197 and 198, 



Ocypoda pugilalor, S.\Y, Journ. Acad. Nat. Sciences, Vol. 1, p. 7[. 



Gelasimus vocans. Milne-Edwards, Hist. Nat. des Crustaccs, Vol. 2, p. 54. 



Gi id. Goi7LD, Invertebiata of Mass. p. 325. 



Description. Body broader than long, and broadest in front ; lateral margins rounded, but 

 defined by a slightly elevated line which forms with the anterior margin nearly a right angle. 

 The cornea occupies an oblique space nearly at the tip of the peduncle, which is 0'2 long, 

 with scattering solitary hairs ; the fossa or furrow for its reception is narrow, nearly straight, 

 and serrated and rounded on its under margin. The antennae are hairy at their bases. Cheeks 

 densely hirsute ; abdominal segments polished, long, sublinear. The enlarged hand occurs 

 indifferently on the right or left, but I think most frequently on the left side, and is often more 

 than twice the length of the transverse diameter of the body. The movable finger is curved, 

 and extends beyond the tip of the other, which is almost straight ; from this results a figure 

 somewhat resembling the bow of a violin, and has probably suggested its popular name of 

 Fidler Crab. The inner margin of the movable finger has a double series of equal tubercles ; 

 the hand is minutely tubercular ; the small hand has its fingers equal, and hollowed inwards 

 as if bent : all the feet with rigid hairs. 



Color, soiled brown above, with a bluish green mark on the anterior part of the shell ; after 

 death, the upper shell becomes polished black, with horn color towards its margins. Eyes 

 black ; peduncles light yellowish ; hands and feet horn-color. 



Length, 0*5. Transverse diameter, 0"6. 



Var. A. Smaller and darker colored ; the shell is not as ventricose, the anterior border more 

 sinuous, and the posterior margin more narrowed behind (fig. 10); the lateral angles are 

 much more acute, but in other respects I find no important difference. 



This species, occupying oblique holes in marshes near the sea, occurs along our whole 

 Atlantic coast as far as Cape Cod. In its movements, which are very rapid, it carries its 

 enlarged hand raised from the ground, and, upon the slightest alarm, elevates it, and extends 

 the fingers in a menacing attitude. This bold demeanor has doubtless given rise to the name 

 of Soldier Crab. At the approach of winter, these holes are closed, and the animals remain 

 torpid until the following spring. They appear to be equally at home on land or in water, 

 but seem to spend most of their time on land. They are of little economical use, except as 

 bait for fish, more particularly the Black-fish, or Tautog. 



