160 THE ZOOLOGIST. 



private gardens, and equally few have a knowledge of the fauna 

 and its environment in the larger detail of their own neighbour- 

 hoods. Dr. Shelford has produced a volume which will not only 

 incite this study but prove a model for that purpose ; it is rich 

 in observational information and focusses attention on the 

 environmental causation of many animal communities. 



There is a very useful discussion on our methods of animal 

 protection. " Mistaken and sentimental ideas cause the killing 

 of many useful animals and the protection of many noxious 

 ones. The farmer kills Snakes and Skunks whenever he has the 

 opportunity, though they are among the most useful animals." 

 Shrews are frequently killed, though they are destroyers of Mice, 

 as is also the case with the House Centipede, though it is the 

 enemy of household pests, &c. Dr. Shelford is not a theorist, 

 and he does not advocate some very prevalent and popular 

 suggestions. Thus, we read in his summary of mimicry : — 

 " One species of insect (or other animal) resembles another. 

 The theorist finds or thinks one of them is distasteful to birds 

 (or other animals). He further discovers or concludes that the 

 species, not having a bad odor or taste, is not eaten by enemies 

 because it resembles the distasteful species. The species having 

 the bad odor or taste is the model. The species not having the 

 bad odor or taste is the mimic. The mimic arose and attained 

 its perfection because those individuals of the mimic species 

 which resembled the model species survived." The argument is 

 at least clearly stated, though its conclusion is apparently un- 

 accepted, and this is not to be regretted, for a theory may be 

 sound and probable, but liable to be distrusted through extreme 

 advocacy and by the sometime employment of unsifted evidence ; 

 opposition thus becomes a tonic. 



