INTRODUCTION. 



our belief in it tends to increase with study and experience. Simulta- 

 neously with the growth of that conviction, however, we also experience 

 a simultaneous growth of scepticism with respect to our power of deter- 

 mining the precise course which specific evolution has followed. Phylo- 

 geny, or the science of such evolution of forms of life, seems to us to be not 

 merely in its infancy but rather at a low stage of embryonic development. 

 We have already seen the overthrow of a great many promising and 

 carefully drawn out genealogical trees of life, and therefore feel little 

 inclined to attempt now to construct the pedigree of the Dog family. 



The palaeontological history of the Canidcs is as yet very incomplete 

 and unsatisfactory, and only permits the formation of speculative opinions 

 which appear to us to be of very doubtful value. Moreover, as we have 

 said, this work is intended to make known living Canidce that is to 

 say, the most divergent forms into which the group, whatever its origin, 

 has become differentiated. For this end, Palaeontology affords no help, 

 since the further we go back the less differentiated we must expect such 

 remains, as may be discovered, to be. So far as we yet know, no fossil 

 Canidce present us with nearly such exceptional forms as are found 

 amongst fossil Feline animals*. Had such been found, they would have 

 demanded careful description here. 



The most diverging groups of the existing terrestrial Carnivora, 

 besides the Dogs, are the Bears, Weasel-group, Civets, Hyaenas, Raccoon- 

 group, and Cats. In the world as we see it, the Dogs stand quite aloof 

 from all the others. The once supposed affinity of the Hyaena-Dog (Lycaon 

 pictus] to the Hyaena, and the Raccoon-Dog ( Canis procyonoides) to the 

 Raccoon, was due to mere superficial resemblances in external aspect. 

 But the triangular fibrous structure attached to the pubis strongly 

 reminds us of the marsupial bones of the Opossum Order (Marsupialia), 

 and it has been suggested that since the Dogs diverge so much from 

 the existing Carnivora they may be survivors of very early forms which 

 had a close genetic affinity with the Marsupialia. The idea is supported 

 by the facts (1) that there is a considerable resemblance in form, and in 



* Such as the extremely modified forms Machoerodus and Eusmilus. See The Cat/ 

 pp. 432 & 437, figs. 184 & 190. 



