CRUSTACEA CASPIA. 359 



Remarks. — The Gammarus caspius of Sp. Bate may perhaps be refer- 

 able to this species, but, as above stated, this name was given a long time 

 ago by Pallas to 1i very different form. In the collection of Dr. Grimm 

 this species has been labelled in 2 different manners. On one bottle, contain- 

 ing an unusually large male specimen, in which, by some accident, the dorsal 

 spines of the 1st segment of the urosome were rubbed off, the name G. 

 robustoides is given; 2 other bottles, containing several considerably smaller 

 specimens of the same species, are labelled with the name G. aralo-caspius. 

 I think I am right in preferring the former name, as the latter is inconve- 

 niently near G. caspius, which is a very different form. The species is easily 

 recognized by the strong and densely crowded dorsal spines occurring on 

 the 2 anterior segments of the urosome. 



"O^ 



Description of the Teniaie. 



The length of adult ovigerous specimens amounts to about 17 mm., but 

 in some places they would seem not to attain to such a large size. In every 

 case this form must be reckoned among the larger -sized species of the 

 genus. 



The body (see fig. 1) is of a rather robust form and but little com- 

 pressed, the back being broadly rounded and perfectly smooth. 



The cephalon about equals in length the first 2 segments of mesosome 

 combined, and has the lateral lobes rather projecting and somewhat ob- 

 liquely truncated at the tip, with the lower corner more prominent than 

 the upper. They are defined posteriorly by a rather deep emargination 

 encircling the large, globular basal joint of the inferior antennae. 



The anterior pairs of coxal plates are of moderate size, and densely 

 fringed on their distal edge with delicate bristles. The 1st pair (see fig. 3) 

 are very slightly expanded in their outer part, whereas the 2 succeeding 

 pairs (see fig. 4) are nearly of same breadth throughout. The 4th pair (see 

 fig. 5) are, as usual, the largest, though scarcely as broad as they are deep; 

 their posterior expansion is vertically truncated, and, like the distal edge, 

 densely fringed with bristles. 



The epimeral plates of the metasome are well developed, and the 2-nd 

 pair a little deeper than the last, both being acutely produced at the lateral 

 corners 



The urosome (comp. figs. 17, 18) is of moderate size, and has the 2 an- 

 terior segments somewhat elevated at the end dorsally, whereby 2 obtuse 

 dorsal prominences are formed, each armed with a number of densely 

 crowded spines arranged in a somewhat angularly bent transverse row. The 



*H3.-MaT. CTi). 339. 17 



