MUSEUM OF COMPARATIVE ZOOLOGY. 69 



pods like those of the external maxillipecls. The first and second pairs of legs 

 are slender, do not reach the tips of the external maxillipeds, and are very 

 nearly alike, but the carpus and chela are a little longer and' more slender in 

 the second than in the first pair. In both pairs the merus is a little longer 

 than the ischium, and reaches to or a little by the antero-lateral angle of the 

 carapax. In the first pair the carpus is scarcely more than half as long and 

 about as stout as the merus, and the chela is somewhat longer and a little 

 stouter than the carpus, and with slender slightly compressed and nearly 

 straight digits about a third of the whole length. In the second pair the carpus 

 is scarcely as stout as the merus and about two thirds as long, and the chela is 

 scarcely stouter than the carpus, but considerably longer. The third and fourth 

 pairs of legs are nearly alike and reach by the tips of the external maxillipeds, 

 the lower edges of the meri are spinulose, the propodi considerably longer than 

 the carpi, and the dactyli are slender, nearly straight, unarmed, and nearly a 

 third as long as the propodi. The posterior legs are slightly shorter than the 

 third and fourth, and like them except the distal extremity, which is peculiarly 

 modified. The propodus is slender, about as long as in the third and fourth 

 pairs, is furnished with a few very long plumose setae near the middle, is 

 thickly armed distally along the lower edge with serrately armed and simple 

 setae, and so densely clothed at the tip with long setae as to very nearly hide 

 the dactyl as, which is very short, curved at the tip, and armed with several 

 slender spines. 



The abdomen is large relatively to the cephalo-thorax, strongly compressed, 

 and dorsally carinated except upon the first somite, the carina being most con- 

 spicuous on the third somite, where it projects posteriorly in a very long and 

 slender tooth. There is a similar but much smaller tooth on the three suc- 

 ceeding somites, though in two of the three specimens examined it is nearly or 

 quite obsolete on the fourth somite. The epimera of the four anterior somites 

 are broad and very deep, the height of the abdomen at these somites being as 

 great as or greater than that of the carapax. The first epimeron is as deep 

 as the second, and its anterior edge is slightly concave in outline and projects 

 a little below ; the second is about as broad as high, and approximately orbicu- 

 lar ; the third and fourth project posteriorly in broadly rounded lobes ; the 

 fifth projects posteriorly in an angular lobe obtusely rounded at the tip. The 

 sixth somite is nearly twice as long as the fifth, and about twice as long as high. 



The telson is considerably longer than the sixth somite, very slender toward 

 the tip, rounded and slightly sulcated above, and armed with four or five pairs 

 of stout dorsal aculei on the distal half. The outer lamella of the uropod 

 scarcely reaches the tip of the telson, is about four times as long as broad, 

 tapers very slightly except near the tip, which is ovate and projects nearly the 

 width of the lamella beyond the angle in which the thickened outer margin 

 ends ; the inner lamella is obtusely lanceolate, and considerably shorter and a 

 little narrower than the outer. 



The outer ramus of the appendage of the first somite of the abdomen is long 

 and slender, and like that of the succeeding appendages, but the inner ramus is 



