Crustacea on the coast of New England. 265 



The megalops-stage of C. marmorata is so peculiar that I insert 

 the following description. The length of the carapax is 3-0"""; the 

 breadth between the antero-lateral angles, 1'8 ; greatest breadth, 2-1. 

 The lateral margins of the carapax are considerably expanded over 

 the branchial regions, and the dorsal surface is smooth and strongly 

 convex. The front is broad between the bases of the eyes, tapers to 

 an acute-triangular tip, and is very strongly deflexed so that the 

 terminal portion is perpendicular and the tiji on a level with the 

 sternum ; the terminal portion is also transversely concave in 

 front, so that, when seen from above, it projects only a little in 

 front of the eyes, and shows a slight emargination in the middle. 

 The eyes are large, the diameter being equal to more than half the 

 breadth of the front between their bases, and project considerably 

 beyond the sides of the carapax. The antennae are very slender and 

 scarcely longer than the breadth of the front between the bases of 

 the eyes. The external maxillipeds have already assumed the form 

 characteristic of the adult Calappidje. The chelij^eds are short and 

 very stout, and in general form approach strongly those of the adult, 

 but are smooth and unarmed with tubercles or spines, except upon 

 the prehensile edges of the pincers. The merus and carpus are stout 

 and swollen ; the body of the jjropodus is stout and broadly expanded 

 above distally, but the upper edge is smooth and rounded ; the 

 digital portion is long, slender, bent downward at nearly a right 

 angle to the rest of the propodus, incurved at the very slender tip, 

 and its prehensile edge slightly tubercular. The dactylus is slender 

 and curved like the propodus, so that the tips of the digits cross 

 when the pincers are closed. The prehensile edge of the dactylus in 

 both chelipeds is armed like the digital portion of the jn'opodus, and 

 in one of the chelipeds there is in addition a stout tooth near the 

 base corresponding to the similar tooth at the base of the dactylus in 

 one of the chelipeds of the adult. The ambulatory legs are small 

 and slender, and the dactylus in the posterior pair is armed at the 

 tip with the three long sette usually characteristic of these append- 

 ages in the megalops-stage. The abdomen is small in proportion to 

 the rest of the animal, tapers very slightly distally, and is strongly 

 convex above. The postero-lateral angles of the second to the fifth 

 segment are prolonged downward into obtuse teeth. The sixth seo-- 

 ment is very short, being less than half as long as broad. The telson 

 is as brood as the sixth segment, but shorter than broad and with 

 the posterior margin nearly semicircular. The appendages of the 

 second to the fifth segment of the abdomen are of the usual form and 



