216 G. 0. SAKS, 



both sexes, very unequal iu size, the posterior ones being much stronger 

 than the anterior, and in male very powerful, with the propodos exceedingly 

 large and swollen. The 2 anterior pairs of pereiopoda normal, the 3 post- 

 erior pairs rather stout, with their outer part edged with fascicles of strong 

 spines and scattered bristles, basal joint of antepenultimate pair having the 

 infero-posteal corner slightly produced, that of last pair much larger than 

 in the preceding pairs, and subquadrangular in form, being broader in 

 female than in male and in both sexes produced at the infero-posteal corner 

 to a short, narrowly rounded lobe, posterior edge distinctly serrate. Last 

 pair of uropoda reaching cimsiderably beyond the others, and having the 

 inner ramus small, scale-like, the outer elongated and densely fringed with 

 ciliated seta3. Telson comparatively small, each half having at the tip one 

 or two small spinules. Length of adult female 15 mm., of male 16 mm. 



Remarks. — In all essential points the description and figures given by 

 Eichwald of his G. Immobaphes would seem to accord with the species 

 above characterised, though they certainly are not detailed enough to give 

 full evidence of Jhe identity of both. The description of Eichwald, it is 

 true, was made out from specimens collected in the Black Sea, but he be- 

 lieve that the same species also occurs in the Caspian Sea and that the form 

 recorded by Pallas as (t. 2)idex is most probably the same. As indeed 

 several species b6th of Mysidcs, Cumacea and Amphipoda have been stated 

 to be common to the two Seas, I cannot see any reason, why not the same 

 could be the case with the present species. In every case there is but little 

 chance of believing that the name proposed by Eichwald should be restored 

 by other authors, and it may thus be jn'operly applied to the form in ques- 

 tion. The species may be best distinguished from the earlier known forms 

 by the armature of the urosome and the rudimentary condition of the inner 

 ramus of the last pair of uropoda, as also by the structure of the gnatho- 

 poda in the two sexes. 



A form very nearly allied to the one here treated of has been collected 

 by Dr. Grimm iu great profusion in the southern and middle pai't of the 

 Caspian Sea, partly from very considerable depths. This form, which has 

 been named by that naturalist Gammanis rohustus \), may perhaps turn out 

 to be only a variety of the present species, though it differs markedly by its 

 larger size, the more slender fonn of the several appendage, and by the 

 shape of the dorsal tubercles of the urosome, which are developed nearly in 

 a similar manner to that in G. caspius. 



1) This name has been preoccupied in the year 1875 by Prof. S. Smith for a North- 

 American species. 



^i^s.-MaT. crp. 216. 3^ 



