422 



0. 0. SARS, 



number of Caspian Anipliipoda, which up to this time have been examined 

 more closely, amounts to no less than 53, belonging to 4 different families, 

 viz., Lijsianassid(B, Pontoporciidce, Gammaridm and Corophiidce^ the Gam- 

 marid(B being the family by far the most abundantly represented. At the 

 close of this paper, I shall give a complete list of all the species. 



Fam. LYSIANASSIDiE. 

 Gen. Pseudalibrotus, Delia Valle. 



Syn.: Alibrotus, G. 0. Sars (olim). 

 Remarks. — In his great work on the Gammarids of the gulf of Naples, 

 Mr. Delia Valle observes that the well-known arctic form Anonyx littoralis 

 Kroyer, which I had referred, though with some hesitation, to the genus 

 Alibrotus of M-Edwards, is scarcely congeneric with the type of the latter 

 genus, A. chauseica. For this reason, he has established the new genus Pseud- 

 alibrotus, to receive the arctic species, and in this view I am now much 

 inclined to agree with that distinguished author. The genus Pseudalibrotus 

 thereby becomes an exclusively arctic one. Now it is rather interesting that 

 this genus is also represented in the Caspian Sea by 2 apparently distinct 

 species, to be described below. 



4 



1. Pseudalibrotus caspius, (Grimm). 



(PI. 1, tig3. 1—20). 



Onesimtts caspius, Grimm MS. 

 » jwmposus, Grimm 6. 

 Specific Characters. — Body rather stout and somewhat compressed, 

 with the back strongly curved. Lateral lobes of cephalon narrowly rounded. 

 First pair of coxal plates much broader than the succeeding ones, and some- 

 what expanded distally; 2nd and 3rd pairs very narrow; 4th pair but very 

 little expanded; 5th pair nearly as broad as they are deep. Last pair of epi- 

 meral plates of metasome acutely produced at the lateral corners. First seg- 

 ment of urosome slightly depressed dorsally. Eyes comparatively small, 

 rounded oval. Antennae somewhat shorter than in the type species, the 

 superior ones with the flagellum twice the length of the peduncle, accessory 

 appendage 4-articulate. Anterior gnathopoda not very powerful, propodos 

 scarcely as broad as the carpus, and somewhat attenuated distally, palm 

 short, oblique, with a single slender spine at the inferior corner. Posterior 

 gnathopoda with the propodos obliquely produced at the tip. Pereiopoda 

 rather short and thick, and but sparsely setiferous; last pair with the basal 



4»ii3.-MaT. CTp. 252. 2 



