2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



nomenclatural problem, and determine whether the species haveintra- 

 generic affinities. 



Materials were collected on the University of Southern California 

 Eltanin (ET) Program and were made available through this office 

 as well as that of Miss Patsy A. McLauglin of the Smithsonian 

 Oceanographic Sorting Center. Dr. Donald F. Squires and Dr. David 

 L. Pawson of the Smithsonian kindly provided specimens from their 

 collections made aboard the icebreaker Eastwind (EW). Miss Naomi 

 D. Manowitz of the Smithsonian, on NSF Grant GB-3285, inked my 

 drawings. 



Echiniphirtiedia K. II. Barnard 



Echiniphimedia K. H. Barnard, 1930. 



Type-species. — Iphimedia hodgsoni Walker 1906 (and 1907). 



Diagnosis (revised). — Acanthonotozomatid with at least 2 or more 

 coxal pairs obtaining submarginal fixed teeth in adulthood, some or all 

 body segments becoming covered with rows or groups of erect cusps 

 on lateral surfaces, teeth also occurring on dorsal surfaces and pos- 

 terior margins of segments but not always distinct from ordinary 

 dorsal and marginal cuspidation of other acanthonotozomatids; 

 epistome broad from side to side, upper lip pendant from epistome and 

 rounded or slightly truncate; mandibles of ordinary shape, neither 

 extremely styliform nor bulky, but relatively simple; incisor of me- 

 dium breadth, serrate or mostly entire; lacinia mobilis vermiform to 

 subvermiform to spatulate, usually entire but occasionally serrate, 

 molar absent; palp of maxilla 1 with 2 articles, reaching or exceeding 

 apex of outer plate; palp of maxilliped 4-articulate, article 4 extremely 

 small but articulate; both pairs of gnathopods minutely chelate 

 (parachelate) ; telson deeply emarginate or truncate. 



Remarks. — The relative consistency in mouthparts, despite minor 

 variations among the three species and strong differences in ornamen- 

 tation, suggests that the genus is internally homogeneous. Three other 

 acanthonotozomatid genera (from a total of 21) have close affinities 

 with Echiniphimedia and, presumably because of simpler ornamenta- 

 tion, may occur on the line of precursors to Echiniphimedia. Pariphi- 

 mediella Schellenberg (1931) seems to be the most primitive of the 

 quartet of genera in that it has a lacinia mobilis in both mandibles. It 

 was distinguished originally from Iphimediella Chevreux (1912) in the 

 serrations of the mandibular incisors, but this character varies intra- 

 specifically in Echiniphimedia and may be of no value as a generic 

 character. Iphimediella, however, also lacks a lacinia mobilis in the 

 left mandible like Echiniphimedia. The former differs from the latter 

 in its vestigial mandibular hump (?molar), a slightly stouter mandible, 

 and a thinner and narrower epistomal sclerite. Pseudiphimediella 



