t 
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2 PROF. G. 0. SARS ON THE COPEPODA [Jan. 12, 
Occurrence.—Of this species specimens were found in samples 
from all three lakes; but only in one of them, taken 13/6/04 in 
the Anchorage Bay, Nyasa, it occurred in any abundance. 
Distribution. —Senegal at Rufinesque (Richard), Sumatra 
(G. O. Sars); ? Germany (Lichard). 
18. CYCLoPs TENELLUS, sp.n. (Plate XIV. figs. 118-127.) 
Specific Characters.—FEMALE. Body (fig. 118) rather slender, 
with very thin and fragile integuments. Anterior division of 
body regularly oval in form, with the cephalic segment very large 
and somewhat truncated in front. Last pedigerous segment very 
small. Urosome slender and narrow, exceeding half the length 
of the anterior division ; genital segment only very slightly dilated 
in front. Caudal rami (fig. 127) about twice as long as they are 
broad and scarcely divergent; seta of outer edge attached nearly 
in the middle, innermost apical seta very small, scarcely longer 
than the outermost, inner mediate seta very slender and almost 
twice as long as the outer, dorsal seta likewise rather much pro- 
duced. Anterior antenne (fig. 119) slender and elongated, 
attaining almost the length of the anterior division of the body, 
though composed of only twelve articulations clothed with slender 
bristles, some of them of quite an unusual length. Posterior 
antenne (fig. 120) likewise rather slender, with a very limited 
number of sete (5) on the penultimate joint. Both pairs of maxilli- 
peds (fig. 121) unusually produced. Natatory legs well developed ; 
terminal joint of outer ramus in the two anterior pairs (figs. 122 & 
123) provided with five slender spines and five sete, in 3rd pair 
(fig. 124) with only four spines; Ist joimt of same ramus, except 
in the Ist pair, without any seta inside; 4th pair (fig. 125) with 
both rami very slender and devoid of the seta inside the Ist joint ; 
apical spines of inner ramus very unequal in size. Last pair of 
legs (fig. 126) extremely small, though apparently of normal 
structure, apical seta the longest. 
Length of adult female 0°38 mm. 
Remarks.—This is perhaps the smallest of all the species of 
Cyclops, and is also distinguished rather conspicuously from the 
other known forms both in its external appearance and the 
structure of the appendages. It therefore appears somewhat 
difficult to decide to which group of the genus Cyclops it should 
more properly be referred. I place it provisionally here, next to 
the three preceding species, to which it exhibits a certain similarity 
as to the general habitus. To judge from its very thin and 
pelucid integument and the delicate structure of the appendages, 
it seems to be a true limnetic form. 
Occurrence.—I have only found this tiny species in two of the 
samples from Tanganyika, one taken 24/2/05 at Baraka, north- 
western shore of the lake, the other 1/3/05 at Kaboge, in the 
same region of the lake. Most of the specimens were more or 
less damaged, owing to the extremely fragile structure of their 
bodies. 
