448 0- 0. SARS, 



with fascicles of bristles intermingled with spines, and in all of them the 

 dactylus is very strong and curved. The basal joint of the ijenultimate pair 

 (fig. 22) is not purticulai-ly broad, but is of a form similar to that of the 

 antepenultimate pair (tig. 21), though somewhat larger. The basal joint of 

 the last pair (fig. 23), on the other hand, is considerably expanded, forming 

 at the infero-posteal corner a projecting lobe, which is naiTowly rounded 

 at the tip. The hind edge of the joint is distinctly serrated, with extremely 

 small bristles springing from the serrations. In the male, this joint (see 

 fig. 28) appears somewhat less expanded, tliough of a similar form. 



The last pair of uropoda (fig. 24) are short and stout, with the basal 

 part very thick, and armed at the end witli strong spines. The outer ramus 

 is but little longer tluxn the basal part, ami does not exhibit any lateral 

 spines, whereas a few such spines, intermingled with slender bristles, issue 

 at the base of the small terminal joint. The inner ramus exhibits the usual 

 scale-like appearance. 



The telson (fig. 25) is considerably broader tliau it is long, aud has the 

 cleft rather narrow. The lateral lobes are obtusely truncated at the tip, and 

 each carry but a single very minute apical si)inule. 



Occurrence. — Several specimens of this form are contained in the col- 

 lection of Dr. Grimm, having been collected partly in the bay of Baku, 

 partly in that of Balchansky. A few spt'cimeus wci'o also collected last year 

 by Mr. Audrussow in the bay of Krasuovodsk. It would seem everywhere 

 to be a sub-littoral species. 



Gen. Gammarus, Lin. 



This genus would seem to be very abundantly represented in the Caspian 

 Sea, and exhibits a very remarkable extent of vai'ial)ility as to the specific 

 characters. To the 1 1 species previously described by the present author, 

 are now added 10 new ones, increasing the number of species to no less than 

 21 iu all, and it is very probable that we are still far from having become 

 acquainted with all the existing forms. 



12. Gammarus Grimmi, G. 0. Sars. 



(PI. 6, figs. 1—10). 



Gammarus robustus Grimm, not Smith. 



Specific' Characters. — Body rather slender and compressed, with the 



mcsosomc and metasome perfectly smooth. Urosomc having the 2 anterior 



segments each produced dorsally to a very prominent tubercle tipped 



with spines; 1st segment with 2 unequal lateral spines; last one with 3 



*H8.-MaT. CTp. 2;«. 28 



