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Show 238 PROF. HUXLEY ON THE CRANIAL AND [Apr. 6, 3. On the Cranial and Dental Characters of the Canidse. By T. H. HUXLEY, F.R.S. [Eeceived March 17, 1880.] Page 1. Introductory 238 2. The method of estimating cranial and dental differences 239 3. Comparison of C. vulpes and C. azarce. Alopecoid and Thooid series . 240 4. Macrodont and microdont forms in each 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 nonlobate mandibles 253 8. The range of modification in the Thooid and in the Alopecoid series... 255 9. The genus Otocyon 256 10. The arrangement of the Canidae 261 11. The aflinities of Otocyon 262 12. The geographical distribution of the Canidae 264 13. The phylogeny of the Canidae 278 14. Conclusion 284 List of Woodcuts 288 1. The unsatisfactory character of the attempts which have hitherto been made to determine the natural affinities of the numerous members of the group of Canine Carnivores must have impressed itself upon the mind of every one w ho has paid close attention 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 purpose ; and it is the less incumbent upon m e to undertake the task at present, as I propose to deal with tbe 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 Canidae 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 number of the praesacral and sacral vertebras alv/ays remains tbe same, and that of the caudal vertebrae varies only within narrow limits. 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 backward extension of the nasal bones, the union or separation of the nasal processes of the frontal bones with the ascending processes of the praemaxillaries, and the variations in the form of the supraorbital processes have been noted. The straightness or angulation of the line 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 |
