512 THE ZOO0OLOGIST. 
We are, however, somewhat puzzled by the Preface as to the 
authorship of this volume. Thus we read :—‘‘ Only one chapter 
in the book (Chapter XIV.) remains practically unaltered from 
the first edition, so that while the credit for the general plan of 
the work belongs to Mr. H. S. Wells, no responsibility attaches 
to him for any part of the present work.’ Who then is the 
writer who has ‘ almost completely rewritten the book”? for we 
are told Mrs. Davies has supplied the diagrams to this volume of 
“the University Tutorial Series.” 
The “type-system” is employed throughout, pages 1-134 
being devoted to a very thorough exposition of the Rabbit. We 
cannot devote a space in these pages sufficient to adequately 
notice the anatomical and physiological treatment of the subject, 
but those of our readers, who do not pay much attention to those 
important aspects of zoology, will still find many interesting con- 
clusions in the life-history of the animal. Many points, often 
overlooked, are brought out very clearly and in plain language. 
‘Thus the Rabbit is dependent on the plant kingdom for the 
maintenance of its life. So, too, are all animals, directly or 
indirectly ; for, though one animal may feed on another, and that 
in turn on another, this process cannot be carried on indefinitely : 
sooner or later we must come down to an animal which is a 
plant-feeder. In the long run all animals are dependent on 
plants for both the material and the energy of their bodies.” 
Again, in rightly estimating a subject so often misunderstood as 
‘‘ variation,” it is well to bear in mind that “it is probable that 
out of the enormous numbers of Rabbits that live or have lived 
no two have ever been exactly alike.’”’ Perhaps, however, a 
strong and excellent theory is made too much a fact, when we are 
told that the upturned white tail of the Rabbit “serves as a 
‘recognition mark’ to guide the young when during feeding an 
alarm is given, and a bolt is made for the burrows.” This isa 
probability ; and even Wallace does not confine its efficacious 
protection to the young alone, but to those “ more remote from 
home,” as well as to the young and feeble. 
Part II. is devoted to the ‘“ Lower Vertebrata,” of which the 
Frog, Dogfish, and Lancelet are taken as types; Part III. treats 
of the “Development of Vertebrata’; and Part IV. deals with 
the “Invertebrata,” the Slipper-Animalcule (Paramecium aurelia), 
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