1909. ] OF THE THIRD TANGANYIKA EXPEDITION. 39 
Il. HARPACTICOIDA. 
The forms of this division found in the collection belong to 
two distinet genera, both of which have hitherto been regarded 
as strictly marine. Hach of these genera belongs to a separate 
family, the one to the Diosaccidee, the other to the Cletodide, 
both families represented in the sea by numerous genera and 
species. 
Family DiosaccipD&. 
One of the most prominent characters of this family, as indi- 
cated by the name, is the presence in the female of two ventral 
ovisacs, a feature very seldom met with in the Harpacticoida, 
and not found in any of the hitherto described fresh-water forms, 
which, like the great majority of marine forms, have only asingle 
ovisac. Indeed, this character was formerly regarded as peculiar 
to the whole division, in contradistinction to the Cyclopoida, 
where constantly two ovisacs are present in the female. The 
present family comprises as yet about five distinct genera. 
Genus Scuizopera G. O. Sars. 
Generic Characters—Body more or less slender, cylindric in 
form, with no sharp demarcation between the anterior and 
posterior divisions. Cephalic segment of moderate size and 
provided in front with a well-developed rostrum, distinctly defined 
at the base, and generally of narrow lanceolate form. Epimeral 
plates of the three succeeding segments rounded. Last pedigerous 
segment without true epimeral plates. Urosome scarcely nar- 
rower than the anterior division; genital segment in female 
imperfectly divided in the middle. Caudal rami more or less 
produced, generally somewhat lamellar, each with a strong spine 
outside accompanied by a slender seta, and with another delicate 
seta arising from the upper face ; tip truncated and carrying three 
sete, the innermost extremely small, the outermost much shorter 
than the middle one, which generally is very strongly developed. 
Anterior antennze in female comparatively short, 8-articulate ; 
Ath joint somewhat produced at the end and carrying a slender 
band-like sensory appendage, terminal part consisting of four 
joints, the last much the longest; those in male hinged in the 
usual manner. Posterior antenne comparatively short and stout, 
geniculate; outer ramus small, biarticulate. Mandibles with the 
palp well developed, biramous. Maxilla and maxillipeds of usual 
structure. First pair of legs more or less distinctly prehensile ; 
outer ramus 3-articulate, and generally shorter than the inner ; 
the latter somewhat varying in structure in the different species, 
consisting of three or only two joints, the first of which is the 
largest and provided inside at some distance from the end with 
a strong ciliated seta. Natatory legs, as a rule, very slender, 
with both rami 3-articulate and provided inside with a very 
limited number of spiniform sete; inner ramus of 2nd pair of 
