The relationship between the palaearctic and nearctic faunas 



231 



This is, however, only part of the explanation of the Amphiatlantic type of 

 distribution though it apparently holds true in the majority of cases, as far as 

 terrestrial Evertebrates are concerned. Putting these aside, there still remains 

 to be considered a good number of animal species which are— or may be— old, 

 prehuman inhabitants of the countries bordering the North Atlantic but are absent 

 from northern and eastern Asia as well as the Pacific side of the American continent. 

 Let us call them the primary Amphiatlantic species. 



The following are good illustrations of this geographical group: — 



A. Primary Amphiatlantic species or subspecies lacking in Asia (except possibly 

 in Novaja Zemlja) as well as in Pacific North America. 



Aves 



Alca tarda L. 



Catharacta skua Briinn.^ 



Cepphus grylle L. (except sbsp. mandti 



Mandt) 

 Charadrius hiaticida L.,/. typ. (incl. 



sbsp. psammodroma Sal.) 

 Fratercula arctica L. 

 Fulmarus glacialis L.,/. typ. (fig. 27) 

 Larus mar inns L. 

 Morns (Sida) bassanus L. (fig. 28) 

 Phalacrocorax carbo L.,/. typ. 

 Sterna dougalU Mont.,/, typ. 

 Thalasseus sandvicensis Lath. 

 Uria aalge Pont.,/, typ. 



Lepidoptera 



Anarta lapponica Thunb. W^ (fig. 30) 

 Crymodes exidis Lef. (fig. 38) 

 Plusia (Autographa) parilis Hbn. W 

 (fig- 31) 



Hymenoptera, Formicidae 



Ponera coarctata Latr. (fig. 35). 



Araneae 



Agyneta cauta Cambr. 

 Crustulina sticta Cambr. 

 Leptyphantes minutus Blackw. 

 Monocephalus parasiticus Westr. 

 Rhaebothorax borealis Jacks. W 

 Walckenaera vigilax Blackw. 



Coleoptera, Staphylinidae 



Micralymtna marinum Strom (fig. 32) 



B. Amphiatlantic species or subspecies differing from group A only in that 

 they extend into Western Asia. 



Aves 



Erolia maritima Briinn. 

 Rissa tridactyla L.,/. typ. 

 Sterna hirundo L.,/. typ. 

 Uria lomvia L.,/. typ. 



Araneae 



Bathyphantes nigrinus Westr. 

 Phlegra fasciata Hahn 



^ Perhaps no permanent resident of North America. 

 * W = "Westarctic" species (vide p. 237). 



