3'S 



Recent Literature. [o^t 



Wallace on 'Palsearctic' and 'Nearctic'. 1 — Again Mr. Wallace comes 

 forward in defence of "the six regions established by Dr. P. L. Sclater," 

 which he still claims as "the most natural and convenient" that "have 

 been established." The reason for this is that "of late years," as he savs, 

 "many eminent naturalists, both in America and Europe, have proposed 

 other regions, though hardly any two of these agree with each other." 

 While this latter claim may be true, they do practically agree in uniting 

 "the Pahearctic and Nearctic Regions so as to form one new region." 

 To refute this grave heresy is the purpose of Mr Wallace's present 

 paper, which, in his own opinion, he succeeds in doing in a very satis- 

 factory manner. But we fear he has not succeeded to any great extent in 

 convincing the heretics. He says, most truly, that u the reason why so 

 much difference of opinion exists on this point, when the very same facts 

 are before all the enquirers, seems to be that they treat the facts in 

 different ways." And the way Mr. Wallace here treats them tends most 

 effectually to mislead and obscure the real points at issue; besides, he 

 makes several misstatements that have an important bearing on the 

 case, as will be noted later. 



Mr. Wallace thinks that "far too much stress is laid upon the compara- 

 tively small number of absolutely peculiar genera or families in the two 

 temperate regions," since, in his opinion, "the facts clearly show that the 

 differences very far surpass the resemblances." In proof of this he 

 tabulates the families and genera of the mammals and the land birds 

 of the two regions, to show which are common to the two and which are 

 peculiar to one or the other. From these tables he educes statistics which, 

 as employed by him, appear to make an excellent showing for his side of 

 the controversy. But to do this he necessarily ignores certain very fund- 

 amental facts and principles. No reference is made, for example, to the 

 eminently homogeneous character of the life of the whole northern half 

 of the northern hemisphere, nor to the fact that the differentiation of the 

 two regions — 'Palaearctic' and 'Nearctic' — is almost wholly limited to 

 their warmer portions; nor to the fact that quite a percentage of the types 

 given by him as peculiar to one or the other of these regions are merely 

 intrusive forms that extend from the tropics northward just a little way 

 into the southern border of his two regions. Furthermore, as regards 

 especially the mammals, about one-ninth of the genera given as peculiar 

 to either the 'Nearctic' or 'Palaearctic' should be transferred to the column 

 of "common to both regions," as for example three of his six genera of 

 Pinnipeds. Besides, no account appears to be taken of the important fact 

 that in comparatively recent geological times the life of the 'Pahearctic' and 

 the 'Nearctic' was much more closely related than at present. 



Mr. Wallace further claims that the differences between the 'Nearctic' 

 and the 'Pahearctic' "are, in fact, fundamental, and are far greater than 



1 The Pahearctic and Nearctic Regions compared as regards the Families and 

 Genera of their Mammalia and Birds. By Dr. Alfred Russell Wallace, F. R. S. 

 Natural Science, Vol. IV, June, 1894, pp. 435-445. 



