ENTOMOSTRACA FROM THE GULF OF ST. LAWRENCE. 47 



Fani. CeNTROPAGIDjE. 



Centropages hamatus (Lilljeborg). 

 Isias clavipes, Boeck. 



Fam. Temorid^;. 

 Temora longicornis (O. F. Miiller). 

 Eurytemora herdmani, I. C. Thompson and A. Scott. 



Fam. PONTELLID^E. 

 Anomalocera pater soni, Temple ton. 

 Labidocera cestiva, Wheeler. 



Fam. AcartiidjE. 

 Acartia clausi, Giesbrecht. 

 Acartia Giesbrechti, Dahl. 

 Tortanus discaudatus (I. C. Thompson and A. Scott). 



Fam. Cyclopid^;. 

 Oithona similis, Claus. 



BRANCHIOPODA. 



Fam. ArguliD;E. 

 Argulus alosce, Gould. 



Fam. Polyphemice (Cladocera). 

 Evadne nordmanni, Loven. 

 Podon polyphemoides, Leuckart. 

 Podon leuckarti, G. O. Sars. 



Notes on the various species. 



Calanus ;?) helgolandicus, Claus. — Calani were numerous in 

 this collection, and were apparently all of the same species, 

 but unfortunately they were nearly all more or less immature, 

 so that among them all I did not find a single adult male; 

 from a careful examination of the largest and most perfect of 

 the specimens, however, I am inclined to ascribe them to the 

 species mentioned above. Calanus helgolandicus has a close 

 resemblance to C. finmarchicus, even in details of structure, 

 so that without perfect specimens the two are easily confounded. 

 Professor G. 0. Sars, in some remarks on the distribution of 

 the two forms, says that C. finmarchicus seems to be charac- 

 teristic of the Arctic zone, being specially abundant between 

 Greenland and Behring Island, whereas C. helgolandicus has 



