inhahiting the New England Coast. 



251 



leave an angular prominence near the middle of the prehensile edge. 

 The dactylus is much longer and less curved than in the male, and 

 its prehensile edge is armed with a small tooth about a third of the 

 way from the base to the tip, and often with minute additional teeth 

 either side of the principal one. 



The first pair of ambulatory legs are slender and scarcely longer 

 than the chelipeds ; the second pair are a little longer and consider- 

 ably stouter, but still slender ; the dactyli in both pairs are rather 

 slender, and in the female nearly as long as the upjjer edge of the 

 propodus, but in adult males appareutly a little shorter. The third 

 pair are very large, about equally stout in the two sexes, and in 

 adults about as long as the breadth of the carajaax, but in young 

 somewhat longer ; the merus is about as long as the carapax and 

 about half as broad as long ; the upper edge is angular and usually 

 minutely denticulated distally, there is a slight transverse gi'oove at 

 the distal end, tlie sides are smooth and rounded, but the inferior 

 edge projects in a thin and conspicuously denticulated carina ; there 

 is a similar but much less cons))icuous carina upon the propodus and 

 also on the ischium ; and there is a slight crest upon the upper edge 

 of the carpus and propodus. The posterior ambulatory legs are 

 short, reaching beyond the merus of tlie third pair, but they are 

 much stouter than the second pair and the merus is carinated and 

 grooved as in the third pair, though much less conspicuously. 



The following measurements of the carapax and one of the third 

 ambulatory legs in a number of specimens show the proportions of 

 these parts of the animal more fully than the description. 



Trans. Conn. Acad., Vol. IV. 



33 



Mat, 1880. 



