216 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 97 
preliminary diagnosis, it is not possible to discuss its relationships 
adequately. It does, however, have 10-jointed ovigers. 
Family PHOXICHILIDIIDAE Sars, 1891 
Phoxichilidiidae Marcus, 1940b. 
The principal characters of this family are the presence of ovigers 
only in the male (there may be rudimentary stumps in some females), 
2-jointed chelifores, and the absence of palpi. The ovigers are 
usually 6-jointed but vary from 5- to 9-jointed. 
The genera and species in this family are vaguely defined; many 
of the species, especially in the genus Anoplodactylus, may be synonyms, 
and all.told the family is a difficult problem for the taxonomist. It 
is of particular interest to the ecologist and student of animal dis- 
tribution because of the pelagic habit of several of its species. 
Three genera, keyed as follows, are recognized in the waters under 
consideration: 
1. Cephalic segment extended forward as a conspicuous neck, overhanging 
insertion of proboscis (auxiliary claws minute) ----- Anoplodactylus (p. 218) 
Cephalicisegment not extended forward! iwi 2 22. 2o2-0 2. 22 Joe ees 2 
2. Lateral processes separated by at least their own diameter; propodus with 
PSG Sg ti 0 it, a a ee oe as eae nee eer rp! Se Phoxichilidium (p. 216) 
Lateral processes separated by less than their own diameter; auxiliary claws 
AIM UEC eee ee Oe et ee a Halosoma (p. 217) - 
[The distinction between Phozichilidium and Halosoma applies only to the 
species in this paper.] 
Genus PHOXICHILIDIUM Milne-Edwards, 18490 
Phoxichilidium Marcvs, 1940b, pp. 36-39. 
Chelifore 2-jointed, chela small. Palpi lacking. Ovigers 5- or 
6-jointed, present only in males. Propodus with prominent auxiliary 
claws. The cephalic segment is not markedly projected over the 
insertion of the proboscis. 
This genus is represented by a single species, P. femoratum, in the 
waters of eastern North America. 
PHOXICHILIDIUM FEMORATUM (Rathke) 
Ficure 24, a 
Nymphon femoratum RAaTHKE, 1799, p. 201. 
Phozichilidium mazillare Stimpson, 1853, p. 37. 
Phoxichilidium femoratum VEeRRILL, 1874a, p. 45. 
Phozichilidium mazillare WiLson, 1878b, pp. 12-18, pl. 4, fig. 1, a-e. 
Phoxichilidium minor WiLson, 1878b, pp. 13-14, pl. 4, fig. 2, a-f. 
Phozichilidium maczillare WiLson, 1880, pp. 480-481, pl. 3, figs. 12-15. 
Non Phozichilidium mazillare Morean, 1891. 
Phoxichilidium maczillare WHITEAVES, 1901, p. 263.—Prarsz, 1914, p. 77. 
Phoxichilidium femoratum NEEDLER, 1948, p. 14, fig. 18, a-{—LxsBour, 1945, p. 
146, figs. 1, a-c, 2a. 
