PREFACE 



Ix the early part of 1897, my brother and I had 

 arranged to collaborate in writing a practical text-book 

 of Elementary Zoology, adapted more particularly to 

 the requirements of Students pursuing courses in the 

 subject as laid down by various examining bodies. We 

 had, however, only reached the stage of deciding on 

 a general plan at the time of my brother's death in 

 November of the same year. 



The following are the chief points on which we had 

 agreed : 



i. To adopt the method pursued in Huxley and Mar- 

 Un's Elementary Biology of giving a connected account of 

 each example. 2. To give brief practical directions which 

 should serve mainly as a guide, the student being able 

 to refer, in case of difficulty, to the descriptive accounts 

 preceding them. 3. In the larger animals, to arrange for 

 as much work as possible to be done on one specimen : 

 there is much to be said in favour of this plan apart 

 from the fact that the average student cannot give 

 sufficient time to the subject to dissect a fresh specimen 

 for each system of organs. 4. To begin the course of 

 instruction by an introductory study of one of the 

 higher animals ; to include in this introduction the 

 elements of Histology and Physiology ; and to select the 

 Frog for the purpose : after trying various methods, I 



