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NOTICES OF NEW -.BOOKS. 

Distribution and Origin of Life in America. By Roperr Francis 
Scuarrr, Ph.D., B.Sc. Constable & Co., Ltd. 
Tuis book is a valuable possession to the student of zoogeo- 
graphy, not necessarily for the acceptance of all the author’s 
theories on the subject, but as a digest of most of the best work 
on distribution to date. He refers to those whose views on the 
subject are not supportive of his own—his and Mr. Lydekker’s 
appear seldom to coincide—while naturally a large number of 
writers are quoted whose conclusions are more in unison with 
those he has formed, the result being that the volume is a guide 
to the work of others on the same subject. 
Dr. Scharff is a strong advocate of former zoological bridges 
in the postulate of long-since submerged continental connec- 
tions, many of which propositions have already received the 
support and dissent of many prominent zoologists; some almost 
necessary conclusions can only be understood on these hypo-.- 
theses, while others appear to scarcely require their insistence 
when other means of dispersion are considered. Although the 
systematist has more frequently worked outside the subject, his 
work has a very important bearing upon it. Species which 
some of the older writers quoted as examples of wide dispersal 
have been since recognized as including several distinct species, 
thus very considerably modifying more than one conclusion once 
generally accepted. The same difficulty applies to the present 
recognition of genera, a previously considered very distinct and 
widely dispersed species often appearing now as a genus com- 
prising several distinct though closely allied species. That this 
must prove a disturbing element in all considerations of faunal 
and floral distribution is obvious. 
No reader, whether he accept the whole thesis of Dr. Scharff 
or otherwise, can carefully peruse this volume with disadvantage, 
