1909. | OF THE THIRD TANGANYIKA EXPEDITION. 53 
19. CycLors aLErpus (Jurine). (Plate XV. figs. 128-130.) 
Occurrence.—-Some few specimens of this well-known species, 
most of them of the male sex, were found in a sample from Lake 
Nyasa, taken 11/6/04 in the Anchorage Bay. I give on the 
accompanying plate a figure of a male specimen together with two 
detail-figures. 
Disiribution.— Kurope, Asia, North and South America, 
Australia, Hawaii Islands. 
20. CYCLOPS ATTENUATUS, sp. n. (Plate XVI. figs. 131-138.) 
Specific Characters—Frmaue. Body (fig. 131) comparatively 
slender and attenuated behind, with the anterior division oval in 
form and evenly rounded in front. Last pedigerous segment 
slightly produced on each side. Urosome somewhat exceeding 
half the length of the anterior division, and gradually tapering 
behind; genital segment only shghtly dilated in front. Caudal 
rami (fig. 138) rather produced, exceeding in length the last two 
segments combined, and of narrow linear form, being not at all 
divergent; seta of outer edge somewhat remote from the end; 
innermost apical seta very thin and about twice the length of the 
outermost, which is somewhat spiniform; the two middle sete 
long and slender, the mimner one exceeding the outer by rather 
more than one-third of its length and almost attaining half the 
length of the whole body. Anterior antennee (fig. 152) compara- 
tively short, not nearly attaining the length of the cephalic 
segment, and composed of only ten articulations. Posterior - 
antennee (fig. 133) of normal structure, with six anteriorly-curving 
sete on the penultimate joint. Natatory legs (figs. 134-136) 
short and stout, with both rami bi-articulate, the last two joints 
being wholly coalesced. Last pair of legs (fig. 137) with the 
proximal joint not defined, its seta issuing from the side of the 
segment itself ; distal joint very small, narrow conical in form and 
tipped with a single seta. Ovisacs small, rounded, each as a rule 
containing only two or three globular ova. 
Length of adult female 0:65 mm. 
Remarks.—This form is nearly allied to the Kuropean species, 
C. varicans G. O. Sars, having, like the latter, both rami of the 
natatory legs bi-articulate, and the last pair of legs partly confluent 
with the pertaining segment. It differs, however, in the some- 
what more slender form of the body, the more produced caudal 
rami, and in the anterior antennz being composed of only 10 
articulations, whereas in C. varicans they are distinctly 12- 
articulate. 
Occurrence.—Several specimens of this form were picked up 
from the muddy deposit contained in one of the samples from 
Tanganyika, taken 13/10/04 at Sumbu, south-western shore of 
the lake, and two specimens, male and female, were found in 
another sample, taken 28/9/04 at Mbete, south end of the lake. 
