474 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Family PSEUDOCYCNIDAE 



Genus PSEUDOCYCNUS Heller, 1865 



Female. — Head fused with first segment; second and third seg- 

 ments free; fourth and fifth segments fused with the genital seg- 

 ments into a cylindrical body several times longer than wide and 

 uniform in diameter. Abdomen 1-segmented ; caudal rami of vary- 

 ing lengths and widths; ^gg strings longer than the body, eggs 

 strongly flattened. First antennae short, with few segments; second 

 antennae stout and uncinate; maxillipeds large, with a toothed ter- 

 minal claw. First legs uniramose, 1-segmented, unarmed; second 

 legs biramose, rami 1-segmented, with setae; third and fourth legs 

 uniramose, with setae; fifth legs obsolete. 



Male. — First segment narrowed into a short neck connecting the 

 head with the second segment; second, third, and fourth segments 

 about the same width; fifth and genital segments fused and the 

 same width as the preceding segments. Abdomen 1-segmented^ 

 abruptly narrowed ; caudal rami flattened, elongated, and armed with 

 spines. Antennae and mouth parts like those of the female; first, 

 third, and fourth legs uniramose, 1-segmented, the fourth pair 

 cylindrical, extended laterally, and half as long as the body ; second 

 legs biramose, rami 1-segmented. 



KEY TO THE SPECIES (FEMALES) 



1. Caudal rami one-third as long as entire body, eight times as long 



as wide, pointed at tip and unarmed appendiculatus (p. 474) 



Caudal rami very short, as wide as long, rounded at tip, each 



with a single apical seta buccatus (p. 476) 



PSEUDOCYCNUS APPENDICULATUS HeUer 



FiGHBB 285, a 



Pseudocycnus appendiculatus Hellem, Reise der Osterreichischen Fregatte 

 Novara, vol. 2, pt. 3, Crustacea, p. 218, pi. 22, 1865.— Wilson, Proc. U. S. 

 Nat. Mus., vol. 60, art. 5, p. 75, pi. 12, 1922. 



Occurrence. — Found on the gills of the long-finned albacore {Orcy- 

 nus alalonga), captured south of Marthas Vineyard, August, 1886. 



Distribution. — Atlantic Ocean (Heller) ; Mediterranean (Richi- 

 ardi, Carus) ; North Atlantic, off Spain (Brian) ; Aden (Bassett- 

 Smith) ; Loyalty Islands (Stebbing). 



Color. — Living specimens are bright red, the oviducts brownish 

 black, deeper toward the posterior end of the body; ovisacs dark 

 brown. 



Female. — Carapace ovate, narrowed anteriorly, the posterior cor- 

 ners prolonged into well-rounded lobes ; the narrow portion between 

 the lobes represents the first segment and carries the first legs. Sec- 

 ond and third segments a little wider than the carapace, each with 



