2.66 PROCEEDINGS OF THE ACADEMY OF [1883. 



ON THE VALOE OF THE " NEARCTIC " AS ONE OF THE PEIMARY ZOOLOG- 

 ICAL REGIONS. REPLIES TO CRITICISMS BY MR. ALFRED RUSSEL 

 WALLACE AND PROF. THEODORE GILL. 



BY PROFESSOR ANGELO HEILPRTN. 



. The subjoined criticism bj' Mr. Alfred Russel Wallace on my 

 paper entitled " On the Value of the ' Nearctic ' as one of the 

 I'rimary Zoological Regions," published in the Proceedings of 

 the Academ}^ for December, 18S2, and my reply thereto, appear 

 in Nature under dates of March 22 and April 26 of this year: — 

 " In the Proceedivgs of the Academy of Natural Sciences of 

 Fhiladeljihia (December, 1882), Prof. Angelo Heilprin has an 

 article under the above title in which he seeks to show that the 

 Nearctic and Pahiearctic should form one region, for which he 

 proposes the somewhat awkward name ' Triarctic Region,'' or the 

 region of the three northern continents. The reasons for this 

 proposal are, that in the chief vertebrate classes the proportion 

 of peculiar forms is less in both the Nearctic and Pahiearctic than 

 in any of the other regions ; while if tliese two regions are com- 

 bined, the}- will, together, have an amount of peculiarity greater 

 than some of the tropical regions. 



" This may be quite true Avithout leading to the conclusion 

 argued for. The best division of the earth into zoological regions 

 is a question not to be settled by looking at it fron:) one point of 

 view alone ; and Prof. Heilprin entirely omits two considerations 

 - — peculiarity due to the absence of widespread groups, and 

 geographical individuality. The absence of the families of hedge- 

 hogs, swine and dormice, and of the genera Meles, Equiis, Bos, 

 Gazella, Mus, Cricetus, Meriones, Dipus and Hystrix, among 

 mammals; and of the important families of fly-catchers and 

 starlings, the extreme rarity of larks, the scarcity- of warblers, 

 and the absence of such widespread genera as Acrocephalus, 

 JIypolai.<, liuticilla, Saxicola, Accentor, Garrulus, Fringilla, 

 Emheriza, Motaci la, Yunx^ C'uculus, Caprimulgus, Perdix, 

 Coturnix, and all the true pheasants, among birds, many of which 

 groups may almost be said to characterize the Old World as 

 compared witli tlie New, must surely be allowed to have great 

 weight in determining this question. 



"The geographical individuality of the two regions is of no 



