1909. ] OF THE THIRD TANGANYIKA EXPEDITION. DD 
than the outermost, which is spiniform; the two middle sete 
rather coarse, almost spiniform, and of moderate length; the inner 
one exceeding the outer by about one-third of its length, dorsal 
seta not much produced. Anterior antenne (fig. 144) compara- 
tively short and thick at the base, consisting of 12 articulations 
densely clothed with slender curved sete especially on the proximal 
part. Posterior antenne (fig. 145) with the seta attached to the hind 
corner of the basal joint rather short; penultimate joint provided with 
nine anteriorly-curving sete, and about the length of the terminal 
joint. Natatory legs (figs. 146-148) short and stout and, as in 
the three preceding species, having both rami bi-articulate. Last 
pair of legs (fig. 149) quite rudimentary, each consisting of only 
a very small conical joint tipped with a single seta, the basal 
joint being wholly confluent with the pertaining segment. Ovi- 
sacs of moderate size, oblong oval in form, and somewhat divergent, 
each containing from ten to sixteen ova. 
Length of adult female 0°86 mm. 
Remarks.—This is a v ery distinct and easily recognisable form, 
being especially distinguished from the three preceding species, 
with which it a grees in the structure of the legs, by the short and 
robust body, the broad, pronouncedly depressed anterior division, 
and the conically produced cephalic segment. It is indeed one 
of the most characteristic endemic forms of Lake Tanganyika, 
and I have therefore thought it right to associate with it the 
name of the distinguished conductor of the Expedition. 
Occurrence.—1 have found this pretty form in four of the 
samples from Tanganyika. In one of these samples, the same 
which contained the above-described species, C. atéenwatus, it 
occurred rather frequently, more rarely in the three other samples, 
‘Of these one was taken 12/12/04 at Karema, eastern shore of the 
lake, another 1/3/05 at Kaboge, north-western shore, and a third 
28/9/04 at Mbete, south end of the lake. 
24. CYCLOPS PACHYCOMUS, sp. n. (Plate XVII. figs. 151-156.) 
Specific Characters.—FEMALE. Body (fig. 151) considerably 
more slender than in C. cwnningtoni, with the anterior division 
less expanded and the cephalic segment obtusely rounded in front. 
Last pedigerous segment about as in that species. Urosome some- 
what exceeding half the length of the anterior division and 
eradually tapering behind. Caudal rami (fig. 156) somewhat 
narrower than in C. cunningtoni, though scarcely longer, and not 
at all diverging ; seta of outer edge attached about in the middle, 
innermost apical seta scarcely longer than the outermost, the two 
middle sete rather slender and elongated, the inner one almost 
twice as long as the outer and exceeding half the length of the 
whole body. Anterior antenne (fig. 152) very short and robust, 
and composed of only 11 articulations thickly covered with 
very coarse, almost spiniform set, several of which are distinctly 
ciliated. Posterior antenne (fig. 153) likewise shorter and stouter 
than in the preceding species. Natatory legs of a very similar 
