Zoological Society. 227 



This species was found in Southern Russia by M. Koppen, and is 

 only from 24; to 3 lines in length. Its principal difference consists 

 in the form of the caudal segment, which is not lobed at the ex- 

 tremity, but is simply squared off and has no setse springing from it. 



Genus Polyartemia, Fischer. 



Corpus molle, gracile; segmentum caudate pinnis nullis instructum ; 

 pedes branchiales, paribus novemdecim. Antennce inferiores 

 maris bi-articidatce, articuli terminates in ramos duos divisi et 

 dentibus numerosis instructi ; articuli basales appendicibm 

 tenuibus armati. 

 Polyartemia, Fischer, MiddendorfFs Sibirische Reise, ii. 154 

 (1851). 



This genus was founded by Sebastian Fischer to receive a species of 

 the family Branchipodidce, which differs in some respects from any 

 of the genera of the family. It is furnished with appendages to the 

 male inferior antennae, which are two-jointed, approaching in this 

 respect to the genus Chirocephalus — and it is destitute of caudal fins, 

 resembling in this structure the genus Artemia — but the number of 

 feet is nineteen pairs, and the male inferior antennae have each of the 

 terminal joints divided into two broad, flat branches, the one over- 

 lying the other like the branches of a pair of scissors. These branches 

 are furnished on their edges with three or four rows of sharp teeth. 

 The basal joint has a rounded process at about half its length armed 

 with short setse. The appendages attached to these organs are coni- 

 cal in form, thin, and apparently not provided with digitiform or fla- 

 belliform appendages. The abdominal portion of the body is shorter 

 in proportion than in any of the other genera, and the ovarian sac of 

 the female is moderately large and lies close upon the abdomen, 

 seeming when viewed from above to be amalgamated with it. The 

 male organ is cylindrical, four-jointed, and is contained in a sheath 

 which is serrated on one side. 



Polyartemia forcipata, Fischer, MiddendorfFs Sibirische Reise 

 ii. 154. t. /. f 24-28. 



As this is the only species yet known, the generic characters given 

 above will suffice. 



Hab. In fluviis "Trundra, Taimyr et Boganida" in Siberia; et 

 prope " Tri-Ostrowa " in Lapponia ; Middendorff. 



Species hujus familice, incertce sedis ant qua dubice sunt 



Genus Branchipus ? 



1. Branchipus ferox, M. Edwards, Hist. Nat. Crust, hi. 369. 



This species, according to M. Milne-Edwards, has neither the an- 

 tenniform appendage attached to the inferior antennse of the male 

 of Branchipus, nor the complicated apparatus of Chirocephalus. 

 They are pointed at the extremity, and thus differ also from these 

 organs in Streptocephalus. The description given of this species by 

 M. Edwards is so short, that it is difficult to say to what genus it 



15* 



