INTEODUCTION. 



§ 1. There are fiye matters of general application : — 



1. The reference to other Publications. 



2. The designation of Weights, Measures and Temperatures. 



3. The names of Animals, and of the Groups to which they belong. 



4. The designation of the Parts of animals, and the indication of their 

 Position and Direction. 



5. The making and arrangement of Notes. 



The treatment of these matters in the present work may be characterized 

 briefly as follows : — 



1. The citations are numerous and explicit. 



2. Only decimal systems are employed, — the Centigrade scale and the 

 Metric system. 



3. The classification adopted is in accordance with generally accepted 

 ■views. 



4. The terminology is intended to have the following features : general 

 application to all Vertebrates ; intelligibility to all nations ; accuracy ; 

 brevity ; simplicity ; consistency ; uniformity of abbreviation. 



5. What may be called the slip-system of notes is recommended. 



I.— EEPEKENOES TO PUBLICATIONS. 



§ 2. We have thought it best to make somewhat full references to other 

 Manuals and Compendiums, and to the Works and Papers of original 

 obfervers. Our reasons are : — 



1. This work is designed to be used not only by the general student, but 

 also, as an elementary introduction, by those who are themselves to become 

 investigators. In our opinion, these latter cannot too soon become familiar 

 with the sources of original information, and with the views of the present 

 and past leaders in scientific progress. 



