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PREFACE. 



In this volume an illustration is given of the opportunity 

 for study in animal bionomics. Mr. Richard Elmhirst con- 

 tributed his own observations on the "yawning" of fishes, 

 a practice little recorded, but one which Mr. Heneage Cocks 

 subsequently showed was long known to himself, though he 

 had looked upon it as a well-known habit common to most, if 

 not all, vertebrates. Other contributors have shown that 

 yawning is not uncommon among Eodents, though Mr. Elm- 

 hirst had been unable to find any records of such a custom, 

 proof being thus afforded of the value of recording bionomical 

 observations which may wrongly be considered as either trivial 

 or within general knowledge. The importance of such facts 

 may easily be underestimated at the time they are published, 

 but they provide material for future generalisations, and always 

 receive a hearty welcome in the pages of ' The Zoologist.' 



In zoological speculation the comparison of animal instinct 

 with reason is a subject which has long exercised philosophers, 

 and is still to be regarded as an open question largely from 

 the imperfect definitions of those two terms. Mr. Dodsworth 

 has again opened the discussion in these pages by his paper on 

 " Mental Powers of Animals," which has in the usual way 

 induced other contributors to record supplementary facts from 

 their own personal observation. This is another field in which 

 many records may appear unimportant, but their value is of 

 a cumulative description, and they supply the material for an 



