No. 1633. LOME NEW ATLANTIC TSOPODA—RTClfA ItDKOX. 73 



in having the first pair of legs prehensile, and not .similar to the 

 following pairs as in that genus, in having the logs furnished with 

 bi-unguiculate dactyli; in not having a bifurcate rostrum, in having 

 the fourth thoracic segment produced laterally in one process and 

 not two, in having the fifth and sixth thoracic segments produced 

 laterally in two processes and not three, in having the lateral margins 

 of the abdomen produced in four large processes and not eight as in 

 that genus. 



It differs from lolanthe Beddard" in (he presence of eyes, in having 

 the first pair of legs prehensile, and not similar to the succeeding pairs 

 as in that genus, in having the fourth thoracic segment produced lat- 

 erally in one process and not two. as in both species of lolcmthe, I. 

 acanthonotus Beddard, and /. decorata Hansen,'' in having the fifth 

 and sixth segments produced in two processes laterally and the sev- 

 enth segment in three, and not as in the two species mentioned in 

 which the lateral margins of the fifth, sixth, and seventh segments 

 are produced in one long spine. In the genus Rhacura the lateral 

 margins of the abdomen are produced in four processes, while in 

 /. acanthonotus there are three long processes and in /. decorata there 

 are eight short ones. 



This genus differs from Ianthopsis Beddard ° in having the first 

 pair of legs prehensile and not similar to the succeeding pairs as in 

 that genus, in having the first and fourth thoracic segments produced 

 laterally in one process and not two, in having the fifth and sixth seg- 

 ments produced in two processes, the seventh in three, and not as in 

 lanthopsis oovallii (Studer),'* which has the last three thoracic seg- 

 ments produced laterally in one long process, and in having four long 

 processes on the lateral margins of the abdomen and not rudimentary 

 ones as in that genus. 



This genus seems closer to Iolella Richardson than to any of the 

 genera referred to above. It differs, however, in having the rostrum 

 reduced to a triangular expansion, in having two lateral processes to 

 the head instead of one, in having one lateral process to the fourth 

 1 thoracic segment instead of two, in having two lateral processes to the 

 fifth and sixth segments and three to the seventh segment, while in 

 Iolella there is one process to each of these segments, and in having 

 four triangular processes to the lateral margin of the abdomen in- 

 stead of one post-lateral process as in Iolella. 



"Challenger Report, Zool., XVII, Pt. 48, Reporl on the Isopoda, Pt. li. 1886, 

 pp. 15-18, pi. iv, figs. 9-14; pi. v, figs. 1-4. 



6 Plankton Expedition, II, 1805, pp. 6-7, pi. 1, figs. 1-le. 



c Challenger Report, Zool., XVII, Pt. 4S, Report on the Isopoda, Pt 2, 1886, 

 p. 15, pi. v, fig. 5. 



d Abb. k. Akail. Wiss. Berlin, 1883, pp. 10-12, pi. 1. fig. 2. 



c Bnll. U. S. Nat. Mus., No. 54, 1905, p. tr.T (footnote). 



