No. 449-] NOTES AND LITERATURE. 399 



ronment. Thus mutation may multiply species without necessitating 

 the extinction of any or requiring the erection of barriers spacial or 

 physiological between the new form and the old one to prevent the 

 swamping of the new form by crossbreeding. A real obstacle to 

 the older ideas about evolution has thus been removed by fuller 

 knowledge of the laws of inheritance of mutations. 



Though a mutation differs from the parent species at first in a 

 single character only, the number of differences is likely to increase, 

 for one mutation leads to another, as observation clearly shows. Ac- 

 cordingly natural selection is presently called upon to make a choice, 

 not simply between two alternative forms, but anion-; several distinct 

 and mutually exclusive types, some one of wliicli will be \n-\W\ 

 adapted to a particular environment than any other. 



The adaptations of organisms are almost endless and iiivolvr tlu- 

 most minute details of structure and function, yet the two principles 



opinion, to account for them all. Natural selection actin.t; merely <>n 

 the fluctuating variations of individuals fails to do this. 



In justice to Darwin it should be said that the mutation or sport 

 forming tendency of species was distinctly recognized by him, but 

 he attached less importance to the process than do Hateson and 

 deVries. The position taken by these writers, and emphasized by 

 Morgan, is that mutations are the exclusive source of the material on 

 which natural selection acts in the production of new species. 



A serious defect of the book from the student's standpoint is the 



ZOOLOGY 



Zoological Investigations in the Malay Archipelago.-- Under 

 the auspices of the universities of txlinburgh and of Liverpool, 

 N. Annandale and H. C. Robinson undertook an '■'^P'-''"^''^*"^^^'^ 

 1901-1 902 for anthropological and zoological 



Malay Archipelago, and some of the zoological results of t leir wor 

 have recently appeared in two fascicles.* The first contains a repor 



