1890.] Recent Literature, 929 
same power of adjusting their color to correspond with a peculiar 
environment. It is well known that the common frog can change its 
tints to a considerable extent. In asserting that the changes of color 
depend upon the eye, and blind animals cannot vary their color pro- 
tectively, Mr. Poulton supports his position by the results of the in- 
vestigations“ of Lister, Brücke, and Pouchet on the physiological 
mechanism of these rapid changes of color. The change of color in 
Arctic mammals is a difficult problem. The seasonal change of color 
in birds is referred partly to aid in concealment, and also to loss 
of susceptibility to cold supposed to result from the white winter coat. 
A never-failing interest attaches to the subject of ‘‘ Warning 
Colors.’’ The history of the discovery of warning colors in cater- 
pillars is quoted with many examples, showing that the education of 
enemies is assisted by the fact that “ warning colors” and patterns 
often resemble each other, and there is abundant evidence to show 
that insect-eating animals learn by experience. By a natural transi- 
tion the writer passes to a consideration of colors and markings which 
direct the attention of an enemy to some non-vital part, and which 
are not attended by unpleasant qualities. An inquiry of great charm 
directs attention to the importance of recognition markings, and the 
principles as set forth by Messrs, Wallace and Tylor. A familiar 
illustration willoccur in the white upturned tail of the rabbit, by which 
the young and inexperienced are shown the way to the burrow by the 
individuals in advance of the expedition. 
In discussing the mimetic appearances of unprotected classes, it is 
made plain that the term mimicry is used for convenience, for the 
mimicking is of course unconscious, so that the use of the word is not 
likely to mislead. 
Mr. Poulton believes that the habits of Bower Birds are evidence 
for the existence of strongly-marked esthetic taste in birds. 
In conclusion, Mr. Poulton brings together the results arrived at by 
investigations, and shows their relation to each other in a system ot 
classification. A detailed table gives the colors of animals classified 
according to their uses, one or more examples accompanying the 
definition of the terms, not those used in the body of the book, which 
were better adapted to illustrate the meaning. The writer believes 
that existing knowledge is well represented by the provisional arrange- 
ment suggested by this table.“ The book is thoroughly illustrated ; the 
frontispiece is a chromo-lithographic plate exhibiting remarkable in- 
stances of mimicry in South African butterflies. Mr. Poulton’s scien- 
tific work has been inspired by his firm resolve to support, in however 
