238 PROF. HUXLEY ON THE CRANIAL, AND [Apr. 6, 



3. On the Cranial and Dental Characters of the Canidae. 

 By T. H. HxjxLEY, F.R.S. 



[Eeceived Marcli 17, 1880.] 



Page 



1. Introductory 238 



2. The method of estimating cranial and dental differences 239 



3. Comparison of C. vulpes and C. azarm. Alopecoid and Thooid series . 240 



4. Macrodont and microdont forms in ea«h series 248 



5. Small and large sagittal areas in each series 250 



6. Nonlobate and lobate mandibles in each series 251 



7. Forms transitional between those with lobate and those with nonlo- 



bate mandibles 253 



8. The range of modification in the Thooid and in the Alopecoid series... 255 



9. The genus Ofocyon 256 



10. The arrangement of the Canidae 261 



11. The affinities of O^cj/ow 262 



12. The geographical distribution of the Oani doe 264 



13. The phylogeny of the Canidse 278 



14. Conclusion -84 



List of Woodcuts 288 



1. The unsatisfactory character of the attempts which have 

 hitherto been made to determine the natural affinities of the nume- 

 rous members of the group of Canine Carnivores must have im- 

 pressed itself upon the mind of every one who has paid close atten- 

 tion to these animals. But I do not think that the discussion of 

 the merits and demerits of the various systems of classification of 

 the Canidse which have been proposed would serve any useful pur- 

 pose ; and it is the less incumbent upon me to undertake the task 

 at present, as I propose to deal with the question in a manner 

 somewhat different, so far as I know, from any which has yet been 

 pursued. 



The general uniformity of the structure of the Canidse is well 

 known. There is a remarkable constancy in the characters of all the 

 organs, down even to the minuter details of the patterns of the 

 crowns of the teeth, accompanied by variations, within comparatively 

 narrow limits, in the form and proportion of the parts. The num- 

 ber of the prsesacral and sacral vertebrae always remains the same, 

 and that of the caudal vertebrae varies only within narrow hmits. 

 In the skull, there is a considerable range in the proportions of the 

 jaws to the brain-case, and in the extent to which the temporal 

 ridges, always widely separate in young animals, approach and 

 coalesce into a sagittal crest in the adult. The greater or less back- 

 ward extension of the nasal bones, the union or separation of the 

 nasal processes of the frontal bones with the ascending processes of 

 the prEeraaxillaries, and the variations in the form of the supra- 

 orbital processes have been noted. The straightness or angulation 

 of the hue of the molar and praemolar teeth, and the proportions 

 of the sectorial teeth to those which follow them, have been taken 

 into account, as well as minor characters of the teeth themselves. 

 Attention has been directed to the excess of teeth above the normal 



