COPEPODS GATHERED BY ALBATROSS—WILSON 315 
Genus PSEUDANTHESSIUS Claus, 1889 
PSEUDANTHESSIUS PACIFICUS, new species 
PLATE 32, Ficures 481-488 
Station 5223. Four females and five males were taken in the surface 
plankton at this station off the island of Luzén in the Philippines. 
Female.—Metasome obovate, narrowed considerably posteriorly and 
without lateral spaces between the segments, the greatest width across 
the posterior margin of the fused head and first segment. Second, 
third, fourth, and fifth segments diminishing in length and width back- 
ward. Urosome more than a third as long and less than a half as wide 
as the metasome and tapered posteriorly. Genital segment as long 
as the first two abdominal segments combined; anal segment twice as 
long as the penultimate segment and invaginated on its posterior mar- 
gin. Caudal rami nearly three times as long as wide, each with five 
setae, the outer one at the center of the outer margin, the others 
terminal. 
First antennae 7-segmented, the segments with the following relative 
lengths: 19, 20, 8, 6, 9, 7, 7, all very setose on the anterior margin and 
the end segment bifurcate at its tip. Second antenna uniramose and 
4-segmented, the first segment considerably swollen at its base, the 
second segment as long as the first and with a short process on the outer 
margin and a slender spine on the inner margin. The third segment 
is the shortest of the four, with a process and two setae on its inner 
margin. The fourth segment has a slender curved claw at its tip, a 
long seta at the anterior distal corner, and two small setae at the base 
of the claw. The mandible passes apically into a long spine toothed 
on both margins, and the palp is a simple fingerlike process with two 
end setae and two on the inner margin. The second maxilla has a 
stout basal segment and a much smaller end segment tipped with a 
curved and dentate spine. The maxilliped is 2-segmented, the end 
segment ovoid and tipped with two curved spines. In the first three 
pairs of legs the outer spines of the exopods are short, ovate, and ser- 
rate, while the setae are long and densely plumose. In the fourth legs 
the outer spines of the exopods are slender and aciculate, with a very 
short spine on each side at the base. The 1-segmented endopod is a 
fiat lamina increasing in width distally, three times as long as its 
greatest width and tipped with two plumose setae as long as the leg 
itself. The fifth legs each consist of a long narrow lamina, slightly 
curved, and tipped with two plumose setae, the inner one as long as the 
leg itself. Total length 3.25 mm. Greatest width 1.20 mm. 
Male.—Metasome elliptical, evenly and broadly rounded at each 
end and about three-fifths longer than wide. Urosome, including the 
caudal rami, more than two-thirds as long as the metasome and 5- 
seemented. Genital segment nearly half as wide as the metasome 
