MUSEUM OF COMPARATIVE ZOOLOGY. 39 



of the orbit, with a prominent slender and acute spine. The lower lateral 

 carina is very prominent anteriorly and is armed with nine to twelve spiniform 

 teeth, of which the three or four most anterior increase in size very rapidly, the 

 anterior one forming a great and somewhat laterally expanded spine nearly or 

 quite half as long as the rostrum, and reaching nearly to, or in the male often 

 considerably beyond, the middle of the antennal scale. 



The eyes are black, very large, pyriform, and including the peduncles much 

 longer than the greatest diameter, which is about two thirds the breadth of the 

 antennal scale. 



The peduncle of the antennula reaches to about the middle of the antennal 

 scale ; the flagella are subequal in length, in the female a little longer than 

 the antennal scale, but in the male much longer and the outer very much 

 stouter than in the female, and considerably thickened vertically. 



The antennal scale is about a third as long as the carapax including the ros- 

 trum, and is itself of nearly the same form as in the allied species, but there is 

 a prominent and acute spine near its base upon the outer edge of the second 

 segment. The distal segment of the peduncle is very long, reaching nearly to 

 the tip of the antennal scale, and the flagellum in the male is about as long as 

 the abdomen, but considerably shorter in the female. 



The external maxillipeds are slender, reach considerably beyond the tips of 

 the antennal scales, and the proportions of the segments and of the exopods are 

 almost exactly the same as in the other species of the genus. 



The anterior legs reach to the tips of the antennal scales : the outer distal 

 margin of the merus is prolonged into a slender spine, and there is a similar 

 one upon each of the two outer distal angles of the carpus ; the chela is about 

 as long as the merus, very stout, somewhat swollen, and nearly cylindrical at 

 base, but compressed and expanded on the inner side distally, the prehensile 

 edge nearly transverse, slightly arcuate, and armed with a very large spini- 

 form tooth at the inner margin. The rudimentary second legs are small, 

 very slender, and reach to the distal end of the ischia of the first : the ischium 

 and merus are subequal in length and each much longer than the three distal 

 segments, of which the carpus and propodus are subequal, while the dactylus 

 is very small, only a little longer than the diameter of the propodus. The 

 third legs reach slightly beyond the first, and the dactylus is very slender 

 and acute, but only about one sixth as long as the propodus. The fourth 

 and fifth are nearly equal in length, and the fourth reach to the tips of the 

 third : the dactyli are about half as long as the propodi, very slender, with 

 the upper surfaces densely ciliated. 



The carinse of the abdomen have the same arrangement as in S. Sarsii, but 

 are much more conspicuous, and each of the epimera of the first two somites 

 projects below into an acuminate spine, while the epimera of the third, fourth, 

 and fifth somites are each armed with two similar spines. The dorsal carina 

 upon the posterior half of the second somite is double, or rather V-shaped 

 with the apex directed forward. The dorsal carina upon the third and fourth 

 somites is very conspicuous, and upon each is prolonged in a tooth at the 



