154 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
with the usual stylet and plumose seta. The latter are of equal length, 
which is about two and a half times the length of the segment. The 
stylet is perfectly smooth and acuminate, and the seta is rather sparsely 
plumed. Total length 1.4mm. Metasome 1.2 mm. 
Male.—Metasome similar to that of female but only three times as 
long as wide and narrowed considerably more posteriorly than an- 
tericrily. Head more or less completely separated from the first seg- 
ment and comparatively short. Fourth and fifth segments completely 
fused and prolonged at the posterior corners into sharp spines, which 
reach the center of the genital segment and are slightly curved out- 
ward at their tips. Urosome about two-fifths as wide and one-third 
as long as the metasome if the caudal rami are included. Genital 
segment widened posteriorly, the lateral margins concave, the pos- 
terior corners each armed with two spines and a smaller one in front 
of them on the lateral margin. The two abdominal segments are the 
same size and rectangular in outline and together are longer than the 
genital segment. ‘The basal segment is unarmed, but the anal segment 
has three minute setae on each side at the anterior corner. Caudal 
rami a little shorter than in the female, nearly as wide as long, each 
with five setae. Four of these setae are on the outer margin of the 
ramus and increase in length distally; the fifth one is terminal, and 
inside of it at the inner corner of the ramus is a minute spine. Here 
again the fan formed by the plumose setae is wider than long. 
The first antennae just reach the anal segment and are quite slender, 
the right one slightly larger than the left. The second antennae, 
mouth parts, and first four pairs of legs are like those in the female. 
The fifth legs are shown on plate 20, figure 269. Each is uniramose 
and 4-segmented, the right one longer than the left. The plumose 
seta on the basal segment of each leg is long and stout, that on the right 
leg at the distal corner, on the left leg at the center of the outer margin. 
The second segment of the right leg has a scalloped inner margin, and 
the third segment has a large rectangular process at the inner distal 
corner. The fourth segment is curved backward around the end of 
this rectangular process. The last three segments of the left leg are 
about the same diameter and diminish in length distally. 
Allotype male.—U.S.N.M. No. 73736, from station 5208. 
Remarks.—The discovery of these males with their peculiar specific 
characters leaves no doubt as to the validity of Dana’s species. Dana 
stated that the females of this species were bluish when alive. As the 
males do not differ from the females in the preserved material, they 
are probably like them when alive. The species does not seem to be 
widely distributed, but since over 100 specimens were obtained it may 
be fairly abundant in limited areas. 
