338 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
these Albatross males there was a fringe of small spines on the pos- 
terior margin of each of the first four urosome segments. Since sim- 
ilar spines are not mentioned in the other species of the genus, they 
will serve as additional marks of identification. It is also worthy 
of note that in the Séboga plankton with one exception these specimens 
were taken in vertical hauls from considerable depth; the tow made 
by the Albatross at this station was also a vertical haul, from 80 fathoms 
to the surface. 
SCOTTOCALANUS HELENAE (Lubbock) 
PLATE 36, FicurEs 548-546 
Undina helenae Lusgock, Trans. Ent. Soc. London, new ser., vol. 4, p. 25, pl. 4, fig. 
4; pl. 7, figs. 1-5, 1856. 
Station 5231. Established by Lubbock upon male specimens from 
the northern Atlantic and placed in the genus Undina; transferred by 
A. Scott in the Siboga plankton to the present genus. It does not 
appear in any of the plankton lists but has been found by several other 
authors. Twenty-five specimens including both sexes, were obtained 
at this Albatross station between Bohol and Leyte in a tow at a depth of 
80 fathoms. The female is described here for the first time. 
Female.—Metasome elliptical, narrowed considerably at each end; 
head fused with the first segment, the separation indicated by a very 
short dorsal groove. The two combined are nearly two-thirds the 
entire length of the metasome, and the head carries a prominent 
frontal crest. Fourth and fifth segments separated, the latter with 
short acute spines at the posterior corners, which overlap the genital 
segment a little. Urosome a fourth as long and wide as the metasome 
and made up of four segments, which diminish in length and width 
distally. In lateral view each segment projects at its posterior margin 
above the following segment. ‘The genital segment is nearly as long 
as the three abdominal segments combined and is slightly protuberant 
ventrally. The anal segment is very short and scarcely visible in 
dorsal view. The caudal rami are well separated, about twice as long 
as wide, and strongly divergent. 
The first antennae are stout at the base but quickly become very 
slender and reach the caudal rami. The exopod of the second antenna 
is much longer than the endopod, and the end segment is about as long 
as the second segment. The mouth parts and first four pairs of legs 
are much like those of other species of the genus, but the fifth legs are 
different. Each leg is made up of three distinct segments, the basal 
segment with a rounded process at the outer distal corner, the second 
segment with parallel sides and the end segment considerably swollen. 
