NO. 1876. ON THE CRUSTACEAN ORDER CUMACEA—CALMAN. 



655 



ond legs have a conspicuous slender spine on the inner side of the 

 ischium; the carpus is longer than the two distal segments together. 

 The posterior legs are very stout ; the carpus of the third pair is as 

 broad as the merus and only a little longer than broad ; no exopods are 

 present on the third and fourth pairs. The peduncle 

 of the uropods, wliich does not quite reach the tip 

 of the telson, has a row of small spines on its inner 

 edge; the exopod is less than two-thirds, and the 

 endopod about one-half, as long as the 

 peduncle; of the three segments of 

 the endopod the first is longer than 

 the other two together; the spines on 

 the inner edge are small. 



The immature male resembles the 

 female in general form. 



Remarks. — This species is very 

 closely allied to D. rathJcii, but it ap- 

 pears to be sufficiently distinguished 

 from that species by the more elon- 

 gated form of the carapace and its 

 less arched dorsal outline, and espe- 

 cially by the marked groove and ridge 

 above the anterior part of its lower edge on each side. 

 The slender form of the cephalothorax and the back- 

 ward projection of the tliird and fourth free thoracic 

 somites, resulting in a gap being left between the 

 second and third pairs of legs, give the species a 

 certain resemblance in general form to Diastylopsis dawsoni. That 

 this resemblance does not imply any close relationship between the 

 two species, however, is shown by the absence in the present ease of 

 any antennal notch, by the large size of the last thoracic somite, 

 the form of the antenna and third maxilUped, and by many other 

 characters. 



Locality.— Alaska,, lat. 63° 37' N.; long. 165° 19' W.; 12 fathoms; 

 G. M. Stoney, June, 1884; U.S.N.M. 44101-44103; 10, male and 

 female (including holotype, 44103). 



Fig. 77.— Diastvlis 

 sulcata, imma- 

 ture female, 

 anterior part 

 of body from 



ABOVE. 



Fig. 78.— Diasttlis 

 sulcata, immature 

 female, last som- 

 ite, telson, and 



UROPOD. 



DIASTYLIS POLITA S. I. Smith. 



Diastylis politus S. I. Smith, Trans. Conn. Acad., vol. 5, 1879, p. 108. 



The specimens that I have examined agree in all essential details 

 with Professor Smith's excellent and minute description. As no fig- 

 ures of the species have hitherto been published, I give outline figures 

 of both sexes to illustrate the cliief differences from D. sculpta. In 

 the female these differences are as follows: The areas between the 

 ridges on the carapace are much less deeply hollowed; there are only 



