no.1843. A NEW ISOPOD GENUS AND SPECIES— RICHARDSON 635 



The first segment of the thorax has the lateral margins produced 

 on either side in one extremely long process, which is as long as 

 the lateral process of the head. The following six segments each 

 have the lateral margins produced on either side in two extremely 

 long processes, as long as those of the first segment. The first 

 three segments and the last three segments each have two sharp 

 spines on the dorsal surface, one on either side of the median line. 

 The fourth segment has four spines, two on either side of the median 

 line in longitudinal series. 



The abdomen is composed of a single large segment. Its posterior 

 margin is produced in two long processes, one on either side of the 

 median line, and its lateral margins are produced in a single long 

 process on either side, posteriorly directed and situated about half 

 the distance from the base to the extremity of the segment. On its 

 dorsal surface is a single median sharp spine on the anterior portion 

 of the segment. The uropoda are composed of a short peduncle, and 

 two branches, not reaching quite to the extremity of the posterior 

 processes of the abdomen, and between which they are situated. The 

 outer is slightly shorter than the inner branch. In a dorsal view the 

 peduncle does not show. 



The first pair of legs are prehensile, the following pairs ambulatory. 



Only one specimen, a male, was taken in the Northwest Pacific, 

 June 7, 1906, at station 4781, lat. 52° 14' 30" N.; long. 174° 13' E., 

 by the U. S. Bureau of Fisheries steamer Albatross, at a depth of 300 

 fathoms, in fine gray sand and pebbles. 



The type, a dried specimen, is Cat. No. 42162, U.S.N.M. 



This species comes from the same locality and depth as Microprotus 

 Cdecus Richardson, 1 and certainly bears a curious superficial resem- 

 blance to that form in the shape of the abdomen, which, however, 

 has only four elongate processes instead of six. In other respects 

 it is closer to Iolella, as previously stated. 



i Proc. U. S. Nat. Mus., vol. 37, 1909, pp. 116-118. 



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