PEEFACE. 



Courses dealing with the anatomy of vertebrate animals form 

 an important part of the curriculum of the college program of 

 studies. Work in anatomy is almost wholly occupied with the 

 gross anatomy revealed by dissection of representative vertebrates. 

 Associated with the course in anatomy is work in embryology in 

 which the emphasis is usually placed upon development in the 

 chick and pig. In addition to embryology and gross anatomy, the 

 student is well repaid by continuing his anatomical studies and 

 investigating the tissue organization of the various systems. 



Although college textbooks in comparative anatomy and embryol- 

 ogy of vertebrates are available, most textbooks in histology and 

 microscopic anatomy have been prepared for medical students and 

 the emphasis has been placed upon human material. In the present 

 book, material has been taken from a variety of vertebrates so that 

 it may serve as a survey of the microscopic anatomy of the verte- 

 brates. 



It is a college textbook, the purpose of which is to present a 

 working knowledge of vertebrate histology and microscopic anatomy 

 to be covered in a semester period. It is not intended as a com- 

 pendium of information on all aspects of so wide a field, and one 

 so rich in interest for investigation. Therefore, the book has been 

 kept primarily on a descriptive basis to accompany laboratory work. 

 The possibility of wide ^•ariation and exceptions in different species 

 make it unavoidable that students will find discrepancies between 

 certain general descriptions and the specific example they may be 

 studying. Since this is true, it is hoped that the student will be 

 interested in discovering variations and will not be content with 

 mere verification of the text. Believing that it is well for the 

 student to acquire the habit of consulting original papers, the 

 authors have appended a few selected references to each chapter. 

 This list of references is in no way complete, but has been selected 

 from the more readily available publications to serve as a starting- 

 point. 



