i] HISTORICAL 17 



the morphologist, whose special business is the study 

 of the anatomical structure and the weighing of 

 these characters as to their classifying or taxonomic 

 value. To see through the resemblances, to see 

 what is due to blood-relationship or descent and what 

 is due to adaptation to similar mode of life is the 

 whole art of the builder of classifying systems, but 

 many of these pedigree problems are still unsolved. 



The study of geographical distribution is now 

 proceeding in two main directions. I. Chorological. 

 According to the method employed this is either 

 zoological geography, proceeding by essays on the 

 faunas of selected countries, and thence, so to speak, 

 letting the research radiate in ever widening circles. 

 An example of this method is Scharff's European 

 Animals. Or geographical zoology, which takes se- 

 lected groups of animals and traces their changes of 

 range in time and space, e.g. Ortmann's Geographical 

 Distribution of Freshwater Decapods. Both methods 

 are of great interest, and each has its advantages in 

 working at the reconstruction of the geography of 

 former epochs. In short they are both essentially 

 chorological, a term which, although strictly meaning 

 distribution in space, must be understood to include 

 the factor of time. II. Oecological, the study of 

 animals with regard to their environment. Instead 

 of searching for pedigrees, or of showing how and 

 when the animals got to the various countries, it 



G. 2 



