330 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
tives of an undescribed species. If the latter alternative is true, the 
male allotype of S. medius diagnosed by Wilson and placed in the 
same vial with the selected “typical” female may have been incorrectly 
assigned to this species.—M. S. W.] 
SCAPHOCALANUS ROBUSTUS (T. Scott) 
PLATE 17, FiguRES 223-226; PLaTE 18, F1iguRES 227-229 
Amallophora robusta T. Scorr, Trans. Linn. Soc. London, ser. 2, Zool., vol. 6, 
pt. 1, p. 56, pl. 4, figs. 24-29, 1894. 
Stations 4590; 5231; 5233. Established by Scott upon specimens 
from the Gulf of Guinea and placed by him in the genus Amallo- 
phora; transferred to the present genus by With (1915, p. 202) in the 
Danish Jngolf plankton. With, however, acknowledged that his de- 
scription did not correspond with that given by Scott; moreover his 
figures were very limited. The Albatross specimens agree very 
closely with those obtained by Scott and for this reason the excellent 
figures made by Sars are here reproduced together with a supple- 
mentary description. 
Female.—Metasome moderately robust but not so much so as in 
Scott’s figure, but the urosome is considerably more robust. The head 
is narrowed but little in front, the forehead is broadly rounded and 
highly arched in lateral view and without a crest. Fourth and fifth 
segments fused, the posterior corners broadly rounded and reaching 
beyond the center of the genital segment, with a very minute spine 
at the apex. Urosome one-sixth as long and almost a third as wide 
as the metasome and 4-segmented. The genital segment is as long as 
the three abdominal segments combined and considerably wider. The 
caudal rami are wider than long, squarely truncated distally, and 
divergent. 
The first antennae reach beyond the tips of the caudal rami and 
are sparsely setose. The exopod of the second antenna is twice as 
long as the endopod and its terminal segment is one-half longer than 
the second segment. The five lateral lobes of the second maxilla are 
well developed, and the end segment is tipped with three cylindrical 
filaments and five shorter ones with ovate heads. There is no trace 
of the filament with an ovate head on the first segment of the maxilliped 
mentioned by Scott, but otherwise the armature is exactly the same. 
The arrangement of the spines upon the third legs is shown in figure 
229, and it will be noted that those upon the endopod are long and 
slender. The fifth legs are 2-segmented with indications that the 
second segment is really two segments fused. It carries a stout setose 
spine on the inner margin and a much smaller and smooth terminal 
spine. Total length 3mm. Metasome 2.65 mm. long, 1 mm. wide. 
