PREFACE 



WHETHEE the student is to specialise in Medicine or Agri- 

 culture or is to pursue a course in Pure Science, his knowledge 

 of Zoology must be founded upon and can only be obtained 

 by personal enquiry with reference to a series of types. The 

 types are selected with a view to his finding out for himself 

 the more important facts of comparative anatomy, physiology 

 and embryology, gaining practice in methods of study, and 

 forming an acquaintance with the literature of the subject. 

 These are the essentials, and should be conveyed by the teacher 

 without undue bias as to the future studies of the student, 

 and without particular reference to the problems which happen 

 to be the fashion of the moment. 



This work is arranged as a guide to the student in acquiring 

 this essential fundamental knowledge. The types chosen are 

 those used in the majority of the Universities and Schools, 

 or are nearly allied to them. More are described than teachers 

 have time usually to accomplish in the First Year ; but in this 

 respect it will meet the requirements of teachers who have the 

 opportunity of adopting the recommendation of the General 

 Medical Council that specialised instruction in Biology in 

 its application to Medicine should be included in the medical 

 curriculum. 



The types are arranged in zoological sequence, and tables 

 are given to indicate their systematic position. Nevertheless, 

 the description of each is complete enough to permit the 

 study commencing with reference to any one of them. The 

 types selected, moreover, are generally distributed, or allied 

 forms may be readily procured, so that the book may be used 

 by students in other countries. 



