29 



Polyartemia forcipata, Fischer, MiddendorfTs Sibirische Reise, 

 ii. 154. t. 7. 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 aut qua dubice sunt — 

 Genus Branchiptjs ? 



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

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



tenniform appendage attached to the inferior antennae of the male 

 of Branchipus, nor the complicated apparatus of Chirocephalus. 

 They are pointed at the extremity, and thus diifer 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 

 may belong. His description is as follows : — " Comes cephahques 

 sans appendice pres du cote interne de leur base, pointues au bout et 

 sans dent sur le bord externe. Abdomen lisse, nageoires caudales 

 longues et etroites. Longueur environ 15 lignes. Habite les eaux 

 douces aux environs d'Odessa." 



2. Cancer paludosus, Miiller, Zool. Dan. ii. 10. t. 48. f. 1-8 ; 

 Herbst, Krabben, ii. 118. t. 35. f. 3-5. 



Most authors have assumed this species to be the same as the 

 Chirocephalus diaphanus. As M. Milne-Edwards very properly 

 observes, however, the figure of this species given by Miiller shows 

 no appearance of the complicated apparatus belonging to the male 

 antennae of Chirocephalus. There does not appear either to be any 

 antenniform appendage belonging to them, as in the genus Branchi- 

 pus, and the structure of the antennae themselves removes it also 

 from the genus Streptocephalus. 



3. Some fragments of a species of Branchipode were brought by 

 Sir John Richardson from Cape Krusenstern in N. America, col- 

 lected there by Mr. J. Rae in August 1849, along with the Apus 

 fflacialis. They consist of portions of two males and two females. 

 The male antennae are two-jointed ; the basal joint is thick, and has 

 at its lower part near its junction with the second a row of small 

 teeth ; the second joint is cylindrical and pointed. The female horns 

 or antennae are flat apparently, and have a short hooked spine at the 

 extremity. The caudal fins are rather long and fringed with long 

 cilia. In some respects this species resembles the figure of the Cancer 

 paludosus of Miiller, but the fragments are too much decayed in the 

 spirits to enable me further to describe it. It does not appear to 

 have either antenniform appendages or any apparatus attached to the 

 antennae of the male. 



Should these three species prove to be distinct, they may form 

 another genus of this family, characterized by the want of these ap- 

 pendages and the toothed or serrated basal joint of the male cephalic 

 horns. 



