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Show 1880.] DENTAL CHARACTERS OF THE CANID.E. 255 siliensis 0f Lund. Under these circumstances I presume that it should be named C. cancrivorus. Another skull of a male animal which died in the Gardens has unfortunately lost its mandible. It is labelled " C. cancrivorus," and differs from the foregoing only in having a much broader sagittal area, with slightly larger teeth and broader and longer palate in proportion to the basicranial axis (though not absolutely) than the foreg_o ing A third skull, also labelled " 0 . cancrivorus," $, is young, with the milk-teeth not yet shed. The permanent first molars above and below are just coming into place ; and their actual dimensions are so nearly identical with those of the preceding skulls, that, though the mandible has not quite the characteristic degree of lobation, I am disposed to think that the differences which exist depend merely on age. 8. If the measurements of tbe skulls of C. azarce (a), C. cancrivorus, and C. azaree be now compared with one another and with those of C. aureus, C. anthus, and C. lupus, they will be found to form a gradual series of modifications. TABLE VI.-Proportional Measurements of the Skulls and Teeth of Thooids. C. azarce C. cancri- C. an- (a). varus. C. azarce. C. aureus, thus. C. lupus. Length of basicranial axis 100 100 100 100 100 100 Length of ^^ 224 27r5 263 27 30 32-5 » ., - 17-7 20-8 19-4 21*4 204 23*2 „ „ - Ill 125 12*1 12 13*6 12*5 „ - 27*7 29*1 30 309 34 369 „ -£ 14-4 15*6 15-7 171 163 171 „ palate 12.3 125 150 124 137 146 Breadth of palate ... 78*9 79 85 94 95 99 The only considerable break in the regularity of the progression here arises from the large size of ^ - in C. cancrivorus and the unusual length of the palate in C. azaree. This regularity, however, is fortuitous. The measurements here given are those of individual skulls ; and if several individuals of any given species are measured in the same way, the range of variation in some cases is remarkable. Thus, three specimens of the Indian Jackal yield the following results (basicranial axis = 1 0 0 ) : - PROC. ZOOL. Soc-1880, No. XVII. \7 |