(XXXVI) | CRUSTACEA CASPIA. 299 
two sexes; 3rd and 4th pairs in female with a small biarticulate appendage 
(rudiment of exopodite) on the basal joint. Pleopoda in male 2 pairs, both 
imperfectly developed; the anterior ones consisting each of a laminar basal 
part edged inside with strong plumose setze, and a single small ramus carrying 
at the tip a few curved setze; the posterior ones quite rudimentary, forming 
2 small claviform appendages, without any setze, but each carrying outside 
à strong spine. Uropoda with the inner ramus uniarticulate, the outer 
biarticulate. Telson very small, unarmed, but distinctly defined from the 
last segment. 
Remarks. — The present genus, the type of the family Pseudocumide, 
was established by the author in the year 1864, to include a Norwegian 
species, which he at first described as Pseudocuma bistriata, but subsequently 
identified with a form rather imperfectly described by Prof. P. v. Beneden 
as Leucon cercaria. In 1876 the same species was also found to occur in the 
Mediterranean, and, in addition, another nearly-allied species, P. ciliata, was 
detected. Though the author has had an opportunity of examining numerous 
Cumacea from very different parts of the Oceans, no other species of this 
genus had before come under his inspection. It was therefore highly per- 
plexing to find this genus, so poorly represented in the Oceans, truly abounding 
in species in the Caspian Sea, and, moreover, presenting forms of a very 
considerable size, as compared with the 2 earlier known species. As above 
stated, the Caspian species also exhibit a most wonderful diversity as to their ` 
outward appearance, some to certain extent recalling in form the genus Dia- 
stylts, others the slender genus Iphinoé, while others again exhibit a perplex- 
ing resemblance to the genus Eudorella. The question now arises, whether 
all these forms can in fact be assumed to have immigrated in some remote time 
from the Oceans, or whether they may, under particularly favourable con- 
ditions, have developed themselves independently from a few, or even a single 
primitive form. The scantiness of species of this genus in the Oceans would 
indeed seem to support the latter supposition. In every case the character 
of the Cumacean fauna of the Caspian Sea, as yet known, is so highly remark- 
able, that some hypothesis is needed to explain it satisfactorily. 
With the exception of P. pectinata, which has recently been detected by 
Mr. Sowinsky in the Sea of Azow, all the species here described are, as yet 
known, wholly restricted to the Caspian Sea. 
1. Pseudocuma pectinata, Sowinsky. 
(PL I & ID. 
Pseudocuma pectinata, Sowinsky: Ο pakoo6passsıxp AsoBckaro Mops, CoÓpaHHEIXt 
A. A. OcrpoymosuiMms Bo BpeMA miaBaHis Ha TPAHCUOPTÉ «Ka36ext» abtroms 1891 roxa. p. 7. 
(TIporokoas: Kies. Οὔπι. Ecrecrsoncnsrrarezeï 1892). 2 
Mélanges biologiques. T. XIII, p. 463. 
