294 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



C. hyperboreus, formerly passed over as a mere Arctic 

 vatiety of C. finmarchicus, but now separated by Gies- 

 brecht as a distinct species. Besides being of a uniformly 

 larger size than C. finmarchicus, it differs from the latter 

 in having lateral nipple-shaped projections at the termina- 

 tions to the cephalothorax, in the large square-shaped 

 first joint of the abdomen, and in the form of the basal 

 serratures of the fifth pair of feet. 



From the peculiar brittleness of the anterior antennae 

 and the swimming feet, it is a rare thing to find anything 

 approaching a complete specimen of this species. 



While expressing in a previous paragraph the general 

 extent to which this collection bears out Dr. Murray's 

 remarks on Antarctic fauna, a considerable exception 

 must be taken to his remark — " Some of these animals 

 seem to be nearly, if not quite, identical with those found 

 in high northern latitudes, and they have not been met 

 with in the intervening tropical zones." As regards the 

 species last alluded to — Calanus hyperboreus — the state- 

 ment is strictly applicable, this species not having been 

 found, so far as I am aware, between the North and 

 South Shetland Islands, represented by 60° N. lat. and 

 60° S. lat. But Calanus finmarchicus has been reported 

 from Australia, 37° S. lat., and I found it at the Canary 

 Islands, 30° N. lat. So there is hardly good reason to 

 suppose that it could not survive an extreme tropical 

 heat, and it might easily migrate across or be carried by 

 a vessel. 



Pseudocalanus elongatus, also well-known as a northern 

 form, was common throughout the gatherings. It has, 

 however, even less claim than Calanus finmarchicus to 

 be classed as exclusively bipolar, as I recently found it in 

 some plankton sent to me by Staff-Surgeon P. W. Bassett 

 Smith, collected in the Indian Ocean. Metridia longa 



