siderably for physiology, especially for the 

 nervous and reproductive systems. No ade- 

 quate schedule of categories could be found 

 for psychobiological literature. The one 

 used owes much to Spence's review of learn- 

 ing and the higher mental processes in 

 infrahuman primates (no. 3308) and to 

 Comparative psychology, by Warden, Jen- 

 kins and Warner (no. 3309). In it we have 

 attempted to phrase the subject headings 

 in non-mentalistic terms. 



It is scarcely necessary to dwell on the 

 difficulties of classifying the literature of 

 functional sciences, especially of psycho- 

 biology, but a few words of explanation 

 may assist the user. It early proved neces- 

 sary to distinguish between experimental or 

 controlled, systematic observational stud- 

 ies and the large class of observational, 

 anecdotal and "popular" literature which 

 is grouped under Habits in nature and cap- 

 tivity. The latter, being largely opportun- 

 istic rather than systematic, defies classifi- 

 cation under any topic heading and often 

 analysis for the purpose of cross referenc- 

 ing. By breaking it down according to 

 family and genera, the volume of literature 

 which needs be consulted is reduced. Where 

 this type of literature deals with definite 

 topics and in some detail, it is cross refer- 

 enced to the expansion under experimental 

 psychology. On the other hand, a few field- 

 studies of a more formal and comprehen- 

 sive character are included in the topical 

 expansion, and this is especially true of 

 studies of social and reproductive behavior 

 where true experimenting is just commenc- 

 ing. Though a more detailed classificatory 

 scheme for psychobiology was initially de- 

 vised, in the end it was found that only 

 relatively large categories were feasible. 

 Whatever the initial zeal, the discomforts of 

 Procrustean categories soon convinced us of 

 the folly of attempting to divide a literature 

 where definite lines of cleavage do not exist. 



The section on the Phytogeny of the pri- 

 mates requires a word of explanation. Since 

 many of the anatomical papers are dis- 

 cussed in relation to the problem of pri- 

 mate phylogeny, we have tended wherever 



possible to throw articles to the system or 

 organs described rather than to the rubric 

 Phylogeny. Thus, for example, discus- 

 sions of phylogeny which deal at all com- 

 prehensively with all of the systems or with 

 one system are usually assigned to the re- 

 spective sections for comprehensive and 

 general works. This, we feel, avoids unde- 

 sirable dispersion of the literature dealing 

 with a given structure. The section on 

 Primate culture and methodology is the only 

 one which truly suffers by dividing the 

 bibliography into two parts. The literature 

 of disease, so important to primate culture, 

 will appear in the second volume under 

 bacteriology and parasitology. 



STYLE AND FORM 



Serial number. References are cited by serial 

 number in the Index of authors and in the cross 

 references coming at the end of each section. 

 The literature to 1800 is cited by author with 

 the number of the Introduction in which the 

 item appears. A serial number marked with an 

 asterisk indicates that the item has not been 

 checked and analyzed from the original source; 

 usually they have been checked from some bib- 

 liographical source. Such unchecked items are 

 estimated to constitute 1 .6 per cent of the whole. 



Authors' names. The surnames of authors 

 are given as they appear in the original source. 

 Authors' names or initials in square brackets 

 have been supplied. For journal literature, ini- 

 tials were considered sufficient; but to distin- 

 guish female authors their given names are 

 spelled out. For books, theses, and other sepa- 

 rate publications we have attempted to supply 

 the full given name, and in the Historical in- 

 troductions, the dates of birth and death as well, 

 since this facilitates the finding of a book in the 

 catalogues of large libraries. 



Titles. Separate publications are distinguished 

 from periodical literature by writing their titles 

 in italics, and their place of publication, etc. in 

 roman. Titles, including subtitltes, are gener- 

 ally given in full for articles and books pub- 

 lished since 1800. Occasionally obvious errors 

 have been corrected to avoid the supercilious 

 [sic]. Capitals, in accordance with the modern 

 tendency, have been avoided except where ab- 

 solutely demanded by the usage of a given lan- 

 guage, i.e., in German and Danish. Scientific 



[xviij 



