42 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



Are the larger pelagic fish forms actually the same for these two oceans, or does 

 each have their own characteristic species? So little is at present known about 

 this that one assumption appears to be valid as the other. We are inclined 

 to prefer the latter, and do therefore not wish to accept that the same species 

 of parasitic crustaceans occur in both oceans as long as a possible comparison 

 is lacking. 



The wide distribution and the similar and unique morphology 

 of the E. nordmanni-E. nymjpha-E. coryphaenae complex indicates, 

 to this author, that these 3 species are synonymous. 



Elytrophora Gerstaecker, 1853 



Diagnosis. — Cephalothorax consisting of cephalon and first 4 tho- 

 racic segments, frontal region distinct; lateral margins with slight 

 indentation medially. Free fourth pedigerous segment with alae 

 extending posteriorly over anterior region of genital segment; fe- 

 male alae with sharp indentation medially, male alae with or without 

 slight indentation. Female genital segment variable in size and 

 shape, longer in egg-producing females than in immatm'e females, 

 with pair of posteriorly projecting, lobe-shaped plates, plates straight 

 or angled inward slightly. Male genital segment without plates. 

 Abdomen 2-segmented, fh'st segment of female with small, posteri- 

 orly projecting lateral lobes, lobes of variable size and shape; first 

 segment of male without lobes. Second segment of abdomen with 

 small, bilobed anal projection. Antennule 2-segmented; antenna 3- 

 segmented, with clawlike terminal process (male with small second- 

 ary spine at base of terminal process). Mandible rodlike, with 12 

 denticulations on inwardly cm'ved distal region, Maxillule nodular, 

 bearing setules; maxilla 2-segmented; postoral process spinelike, 

 distal region more slender in mature specimens than in immature. 

 Maxilliped 2-segmented, with clawlike terminal process. Thoracic 

 legs I-IV bhamous although endopodite of first and fourth legs re- 

 duced; ramal count 2-2, 3-3, 3-3, 3-2. Fifth legs present, setiform. 



Remarks. — The similarity of Euryphorus and Elytrophora is re- 

 markable. This similarity is principally in the general shape of the 

 cephalothorax, the female alae, genital plates, abdominal processes 

 (although they are much larger in Euryphorus), and number of seg- 

 ments in the rami of the first 4 pairs of thoracic legs (identical in 

 members of both genera). 



Elytrophora brachyptera Gerstaecker 



Figures 16-21 



Elytrophora brachyptera Gerstaecker, 1853, p. 60, pi. 3, fig. 12. — Nordmann, 1864, 

 p. 468.— Heller, 1866, p. 753.— Van Beneden, lS70a, p. 57.— Richiardi, 

 1880, p. 3.— Stossich, 1880, p. 257.— Valle, 1880, p. 60.— Carus, 1885, p. 360.— 



