QUEEN CHARLOTTE ISLANDS. 217 B 



third, fourth and fifth pairs of peraeopods are short and as in the 

 species of Diastylis, except that the coxal segments of the third pair 

 are very broad, about four times as broad as high, and closely fitted to 

 the corresponding segment of the peraeon. 



The pleon is cylindrical and slender throughout, very much nar- 

 rower than the cephaloperaeon, and the segments increase slightly and 

 regularly from the first to the sixth. The telson is shorter than the 

 sixth segment, swollen for the proximal half its length, then suddenly 

 narrowed into a slender terminal portion which is armed either side 

 with about five or six very slender spiniform setae, and at the tip with 

 two styliform seta? nearly half as long as the telson itself. The 

 peduncles of the uropods are slender, not quite twice as long as the 

 telson and armed along the distal half of the inner margin with 

 approximately ten very long seta?. The inner ramus is narrow, about 

 half as long as the peduncle, composed of three segments, armed along 

 the inner edge with approximately twelve slender spines, at the tip 

 with a larger spine, and along the outer edge with a few setas. The 

 outer ramus is a little longer than the inner, slender, and armed 

 along the outer edge and at the tip with setiform spinules. The telson 

 and uropods are more or less imperfect in all the specimens examined, 

 and do not admit of very exact description. 



All the males examined are immature and of about the same size as 

 the females. They differ from the females, as in the species of 

 Diastylis, in having rudimentary exopods on the third and fourth 

 peraeopods and in having rudimentary appendages upon the first and 

 second segments of the pleon. The specimens examined show scarcely 

 any differences in the telson and uropods, but these differences would 

 probably be developed in more mature individuals. 

 A female gives the following measurements: — 



Length from rostrum to tip of telson 12-2 mm> 



Length of cephaloperseon along dorsum 6-7 



Length of carapax along dorsum 4-2 



Greatest height of carapax 2-0 



Greatest breadth of carapax 1*8 



Length of 3rd and 4th free segments of perason along 



dorsum 1-8 



Length of pleon to tip of telson 5-6 



The few specimens of this very interesting and pretty species were 

 all from 111 fath., Dixon Entrance, Q.C.I. It is interesting to notice 

 that it was associated with Synidotea nodulosa, a species before known 

 only from the Atlantic. 



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