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



Table VII. — Proportional Measurements of Teeth and Palate of 



Caiiis aureus. 



I. II. III. 



Length of ^^^ 27 31 33-8 



„'^ 22 24 21-6 



„ ^ 12 12-2 13-2 



» » — 1 30-5 34 35-8 



» „ „— 2 17 10-9 16-6 



» " ^3 7-5 7-5 



Length of palate 125 141 143 



Breadth of palate .... 94 90 90 



The actual dimensions in millimetres are as follows : — 



Table VIII. — Cranial and Dental Measurements o/Canis aureus. 



I. II. III. 



Length of basicranial axis. . 59 53 53 



£^' 16 lG-5 18 



^ 13 13 11-5 



^ 7 6-5 71 



— r 18 18 19 



—7, 10 9 9 



-^, 4 4 



" TO. A 



„ palate 74 75 76 



Breadth of „ 56 48 48 



The comparison of these two tables is interesting ; for, according 

 to the first, the variations of the dimensions of the teeth in propor- 

 tion to those of the basicranial axis cover the whole range between 

 Canis azarce and the Wolves ; on the other hand, the second shows 

 that, while the basicranial axis, doubtless following the actual size of 

 the animal, varies considerably, and while the teeth also vary, the 

 two sets of variations do not correspond : hence, in the proportional 

 table, the differences in the sizes of the teeth appear to be greater 

 than they really are. 



Similar results are attained when the measurements of any con- 

 siderable number of specimens of other canine skulls are compared. 

 In fact, while in both the Thooid and the Alopecoid series the species 

 may be arranged in a scale characterized by the gradually increasing 

 relative and actual dimensions of the sectorial teeth, each species 

 occupies not a line but a broad zone upon that scale, which zone is over- 

 lapped by that of the species below and by that of the species above. 



9. The lowest Alopecoids and the lowest Thooids agree in the 

 relatively small size of their sectorial teeth ; and many possess a large 

 lyrate sagittal area and a strongly lobate mandible. The genus 



