93 BULLETIN OF THE 



posed of about ten segments, and armed, like the ischium, meras, and carpus, 

 with exceedingly long, and for the most part simple, setiibrm spines, and at the 

 proximal extremity with a tuft of serrate seta; corresponding to a similar tuft on 

 the distal extremity of the propodus ; the dactylus is very minute, but perfectly 

 distinct, and armed with an exceedingly long and slender spiniform seta, while 

 the tip of the propodus is armed with a very much shorter spine. The legs of 

 the second pair reach to about the tips of the external maxillipeds : the merus 

 is a little longer than in the first pair ; the carpus twice as long as in the first 

 pair and only a little shorter than the merus ; the propodus is longer than the 

 merus, composed of about twelve segments, and armed very nearly as in the 

 first pair, except that the tuft of setse at the proximal extremity, with the cor- 

 responding one on the carpus, is wholly wanting, while the digits of the well- 

 developed chela (Fig. 6) are considerably longer than the diameter of the pro- 

 podus at their base, slender, nearly straight, and armed at the tips with a dense 

 brush of seta?, most of which are serrate. The legs of the third pair are almost 

 exactly like those of the second, except that they are considerably longer, reach- 

 ing by the second pair by about half the length of their dactyli. The legs of 

 the fourth pair reach nearly to the tips of the carpi of the third pair and are 

 veiy much stouter, and the endopods are composed of only four segments each, 

 the dactylus, apparently, being wanting : the ischium, carpus, and propodus (or 

 the proximal and the two distal segments) are subequal in length, while the 

 merus (or antepenultimate segment) is about once and a half as long as each of 

 the otkers : the merus is about six times as long as broad, and, like the ischium, 

 densely ciliated along both edges, but the cilia on the lower edge are several 

 times longer than those upon the upper, which are not as long as the breadth 

 of the segment ; the carpus is slightly broader than the merus, being more than 

 a fourth as broad as long, ciliated like the merus along the lower edge, but the 

 upper edge naked ; the propodus (or ultimate segment) is a little less than a 

 fifth as broad as long, ovate at the tip, and has the lower edge ciliated and the 

 upper naked like the carpus. The legs of the fifth pair are a little more than 

 half as long as those of the fourth, and their endopods are composed of the 

 same number of segments : the ischium and carpus are subequal in length, the 

 merus a little longer, and propodus a little shorter, and all the segments are 

 ciliated along both edges, though the cilia upon the lower edge are much longer 

 than those upon the upper ; the merus is about a fourth as broad as long, and 

 considerably broader than the ischium or carpus ; the carpus is less than a 

 fourth as broad as long, and slightly tapered distally ; the propodus is a little 

 less than a fifth as broad as long, and regularly tapered from near the base to 

 the acute tip. 



The abdomen, excluding the telson, is nearly twice as long as the carapax 

 along the dorsal line, is considerably compressed, though anteriorly about as 

 broad as the carapax, and, like the carapax, rounded above, but with a shallow 

 median sulcus on each of the first four somites, inconspicuous on the first and 

 second, but distinct on the third and fourth. [There are similar sulci on the 

 abdomen of S. arcticus, and they are possibly, though apparently not, due to 



