PREFACE. 
The fourth volume of the ^ Record ^ forms a systematic guide- 
book to about 36,400 pages* of the zoological literature published 
(with the exception of a very small part) within the year 1867. 
This number has never been reached in anj^ preceding year, and 
corresponds to an increase in the number of authors ; an un- 
usually great activity appears to have prevailed in the study of 
Mammals, Birds, Mollusks, Neuroptera, and Orthoptera. 
It has frequently been suggested that the annual volume of 
the ^ Record^ should be divided into several parts, in order to 
facilitate to specialists the acquisition of the reports on their 
own branches. The Editor, therefore, considered it his duty to 
propose to the publisher a division into three sections, viz. that 
of Vertebrates, of Entomology, and of Mollusks, Crustaceans, 
and Lower Animals. Although this arrangement interferes 
with the systematic succession of the Classes of Animals, it ap- 
peared to be practically the most advisable. The integrity of 
the volume is preserved by adhering, in all three parts, to the 
same plan which has been followed hitherto, and by keeping a 
continuous pagination. 
Mr. Spence Bate (who, residing at a great distance from 
scientific libraries, found access to the literature very difficult) has 
resigned his place among the contributors, and Dr. von Martens 
has consented to be his successor. 
* This number is divided between the various classes thus: — Mammals 
4030, Birds 8340, Reptiles 710, Fishes 1180, Mollusks and Moll uscoids 6260, 
Crustaceans 470, Arachnids and Myriopods 640, Insects 13,000 (viz. Coleo- 
ptera 3000, Hynienoptera 1 100, Lepidoptera 2000, Diptera 700, Neuroptera 
and Orthoptera 1100, Rhynchota 000), Annelids 200, Scolecides 370, l^hi- 
noderms 350, Coelenterates 70, Protozoa 770. ' • - , 
