242 POPULATIONS OF THE SEA 



much needed. The origin of the word iidos from edos custom, usage, is 

 clearly given in Aristotle (Ethica Magna, II 6.2; Ethica Endemia II, 

 2.1, Ed. Bekker). The general Greek usage of r]do%, especially in the 

 plural -ridr], as the accustomed seat, haunt, habitat, or dwelling of men or 

 animals, admirably expresses the chorological aspect of "ethology"; its 

 usage in the sense of habit, manners, etc. (lat. consuetudo. mores) 

 expresses what we mean by animal behaviour, while the signification of 

 ridos as character, disposition, nature, etc. (Lat. indoles, ingeniiim, 

 affectus) is well suited to express the psychological aspects of "ethology." 

 Certainly no term could be more applicable to a study which must deal 

 very largely with instincts, and intelligence as well as with the habits 

 and "habitus" of animals. It is apparent from a moment's reflection 

 that the term may be readily made to include all and more than is 

 meant by "Biologic" in the German sense, or "oecology" in the 

 Haeckelian sense. 



Although intended to clarify it seems likely that Wheeler's 

 essay may be partly responsible for some of the loose speaking 

 about ethology and the varying interpretations put upon the word 

 itself. 



J. Arthur Thomson introduced ethology into the Zoological 

 Record for 1901 as a subsection of "I. General Subjects ... 4. 

 Physiological . . . d. Nervous and Sensory: Comparatixe Psy- 

 chology . . . Ethological" ; but in that for 1902 (following Wheeler's 

 essay) David Sharp, who had taken over this section from Thomson 

 put "Ethology" into the comprehensive section while still retain- 

 ing "Comparative Psychology" in general zoology. This situation 

 lasted until the Zoological Record for 1939 when it disappeared 

 altogether as an index subject. No one who regarded some of the 

 subjects included by Sharp in ethology would be surprised at the 

 contents of Pelseneer's (1935) monograph Essai d'ethologique 

 d'apres Vetude des Molluscs, yet it contains hardly a phrase of 

 ethological treatment as now defined or as generally understood. 



The concept of ecology (from Gr. oikos = house, habitat environ- 

 ment), how^ever, has now^ definitely crystallized out of this mix 

 into the more quantitative or numerical aspects and physico- 

 chemical interrelationships of organisms with their environment 

 and with each other. This leaves ethology completely free to be 

 used for the study of the behavioral aspects of these relationships 

 and such others as are generally comprehended in the terms com- 



