1909. | OF THE THIRD TANGANYIKA EXPEDITION. 57 
Remarks.—This form, like the six succeeding species, belongs to 
the group of Cyclops for which C. serrulatus Fischer is the type, 
and which has proved to contain several well-defined species 
formerly generally regarded as only varieties of the said species. 
The present form is nearly allied to C. macruroides Lilljeborg, 
differing, however, in some particulars, for instance in the arma- 
ture of the caudal rami and the mutual relation in length of the 
apical seta, so it may be more properly regarded as specifically 
distinct. 
Occurrence.—This form occurred very abundantly in-one of the 
samples from Tanganyika, taken 19/9/04 at Niamkolo Island, 
south end of the lake. It was not found in any of the other 
samples. 
26. CYCLOPS LEVIMARGO, sp.n. (Plate XIX. figs. 170-175.) 
Specific Characters.—Frmaue. Body (fig. 170) comparatively 
more robust than in the preceding species, with the anterior division 
shghtly dilated in front. Last pedigerous segment and urosome 
about as in that species. Caudal rami (fig. 175) of a similar 
narrow linear form, but with the outer edge perfectly smooth, 
without any trace of the regular row of denticles found in that 
species ; innermost apical seta scar cely longer than the outermost, 
the two middle setz comparatively shorter than in Q. semiser- 
ratus and quite uniformly ciliated, the inner one only exceeding 
the outer by one-fourth of its length and slightly bent outwards 
at the middle. Anterior antenne (fig, 171) much shorter than 
in that species, scarcely attaining the length of the cephalic 
segment, though composed of the same number of articulations. 
Posterior antennee (fig. 172) likewise shorter and stouter. Fourth 
pair of legs (fig. 173) with the spines on the outer ramus com- 
paratively ‘short and blunt at the tip. Last pair of legs (fig. 174) 
with the spine of the inner corner small, though perhaps a little 
longer than in the preceding species. Ovisacs comparatively small 
and scarcely divergent. 
Length of adult female 0°85 mm. 
Remarks.—The present form differs conspicuously from the 
preceding one by the much shorter anterior antenne and by 
the absolute absence on the outer edge of the caudal rami of the 
regular series of denticles generally found in the species belonging 
to this group. It is from this last character that the specific 
name here proposed is derived. 
Occurrence.—Vhis form also was only found in one of the 
samples from Tanganyika, but in this rather abundantly. The 
sample was taken 12/12/05 at Karema, eastern shore of the lake. 
27. CycLops aANcusTUS, sp. n. (Plate XIX. figs. 176-180.) 
Specific Characters.—FrmMaue. Body (fig. 176) very slender and 
narrow, with the anterior division oblong in form and obtusely 
truncated in front. Last pedigerous segment with the lateral 
parts only slightly expanded. Urosome attaining about two- 
