PREFACE vii 



of the dogfish, turtle, and mammal, except the peripheral distribution of the 

 cranial nerves in the mammal. The elasmobranch, urodele, and mammal would 

 make a combination nearly as desirable. 



The general statements and explanations given in the manual have been 

 taken from standard works and original papers on comparative anatomy, verte- 

 brate zoology and embryology, and human anatomy. I have adopted, for the 

 most part, the usual accounts of the evolution of the various systems and parts, 

 not regarding myself as competent to criticize them. In a few cases I have pre- 

 sented some recent views appearing in the literature. The laboratory directions 

 and descriptions of the anatomy of the several animals have, however, been 

 written entirely from the specimens. Practically the whole of the dissection 

 has been performed twice, some of it more than twice. The dissections have been 

 carried on simultaneously with the writing of the directions. In locating and 

 naming the structures I have been assisted by various texts, manuals, and original 

 papers. In a number of cases I have found it desirable to devise additional 

 names or to change old names. I have employed the terms dorsal, ventral, 

 anterior, and posterior as they are used in vertebrate anatomy, abandoning the 

 usage common in human anatomy. This has involved a change in some familiar 

 names, such as that of the "anterior" abdominal vein. 



I have made a particular effort to use all technical words in a very precise 

 and exact manner and to define each such word where it first occurs. One is 

 continually surprised and annoyed in a study of vertebrate structure to note 

 the loose and inexact way in which many terms are employed. It is, in fact, 

 practically impossible to find any precise usage for many terms, such as urethra, 

 bulbus arteriosus, peritoneum, olfactory lobe, perineum, and others. In such 

 cases I have been compelled to adopt such a definition as seems consistent with 

 the majority of the anatomical facts. 



I have attempted nothing in this manual but a plain account of the anatomy 

 of the several animals, which account the student follows. This "verification" 

 type of laboratory manual has been recently subjected to much criticism, much 

 of it, in my opinion, undeserved. The critics seem to forget that the student is 

 not in reality engaged in "verifying" the statements in the manual; he is engaged 

 in learning the anatomy of an animal by the shortest and easiest route, a route 

 which the critics themselves would follow if confronted with an animal with 

 which they were not familiar. It is my opinion that human beings in general 

 see chiefly that which is pointed out to them ; this has been proved over and over 

 again in the history of biology. The large number and complexity of the 

 anatomical facts to be acquired, the limited time allowed for their acquisition, 

 the large size of the classes, and the limited number of laboratory assistants 

 available seem to me to necessitate that detailed and specific laboratory direc- 

 tions be provided. If the directions are not given in the manual, then the labora- 

 tory instructors are compelled to provide them verbally. Personally I am unable 



