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Crustacea caspia. Coniributions to the knowledge of the carcinological 
Fauna of the Caspian Sea, by G. 0. Sars, Prof. of Zoology at the 
University of Christiania, Norway. (Lu le 15 septembre 1893). 
Part II, 
CUM ACE A. 
With 12 autographic plates. 
INTRODUCTION. 
In my former paper on Caspian Crustacea (Mysidæ), I adverted to the 
interesting fact that, in addition to Myside and Amphipoda, also the exclusive 
marine order Cumacea bas turned out, by the investigations of Mr. War- 
pachowsky, to be well represented in the Caspian Sea. It is now my pur- 
pose, in the present paper, to treat of the several forms of the latter order, 
which have hitherto come under my inspection. As will be shown, it is by 
no means, as should, indeed, have been expected, a scanty and depaupe- 
rated Cumacean fauna that inhabits the Caspian Sea. On the contrary, the 
results hitherto gained would seem to prove, that the peculiar physical and 
biological conditions, prevailing in that isolated basin, must have had a 
most beneficial influence on the development and thriving of these interesting 
Crustacea; for the species are rather numerous, and in some places appear 
with a great abundance of specimens. Moreover, several of the forms attain 
a rather large size, as compared with their allies in the Oceans, and are 
only surpassed by some of the giant arctic species of the genus Diastylis. As 
regards outward appearance, the species exhibit rather conspicuous differences, 
being partly rather clumsy, partly extremely slender, and some of them 
‘acquire, moreover, a most peculiar aspect by the strange development of 
dorsal crests on the free segments of the mesosome. To judge from these 
very conspicuous differences in the outer habitus, one would at first be 
‘disposed to believe, that they belonged to several distinct genera. This, 
however, is not the case. For anatomical examination has indeed shown 
them all to belong to one and the same genus, viz., Pseudocuma G. O. Sars. 
Melanges biologiques. T. XIII, p. 461. 
