CHAP. IX.] TEETH : CANUTE. '209 



CARNIVORA. 



CANID.E. 



The evidence of the Variation of teeth in Canid;i' is divided 

 into three groups according as it concerns (1) incisors, (2) pre- 

 rnolars, (3) molars. No case specially relating to the canines 

 is known. In each of these groups the cases relating to (A) 

 wild Canida? are taken first, and those relating to (B) domestic 

 Dogs afterwards. 



Of wild specimens of the genus Canis (including the Fox) 

 289 skulls were seen, and amongst them were 11 cases of super- 

 numerary teeth, about 3'5 per cent, (besides many recorded cases). 

 Of 216 domestic Dogs (including Pariahs, Esquimaux, &c.) 10 

 had supernumerary teeth, or 7'4 per cent, (besides many re- 

 corded cases). I have not included skulls of edentulous breeds, 

 in which the original condition of the teeth cannot be told with 

 certainty. 



Statistics of the occurrence of supernumerary teeth are given 

 by HEXSKL, Morpli. Jahrb., 1879. Among 345 domestic Dogs 

 in his collection there are 28 cases of one or more extra molars, 

 12 cases of extra premolar, and 5 cases of extra incisor. [If 

 therefore no two of these cases refer to the same skull, there were 

 in all 45 cases of extra teeth in 345 skulls, or 13 per cent. It 

 is not stated that the collection was not strictly promiscuous, 

 but it may be anticipated that this figure is rather high.] An 

 analysis of Hensel's cases will be given in the sections relating 

 to the particular teeth. 



The usual dentition of the genus Canis is t|, c\, p^, m'^. 

 The Wild Dog of Sumatra, Java and India, C. javanicus and 

 C. primcevus (by some considered as one species) have wf and 

 have been set apart as a genus under the name Oaon (HODGSON, 

 Calcutta Jour. N.H., 1842, ii. p. 205). The genus Icticyon differs 

 in having normally w|. The genus Otocyon on the contrary has 

 usually m%. 



Of the variations to be described in Canis the most notable are 

 (1) cases of iizi ; (2) cases of extra premolar, common in upper, very 

 rare in lower jaws ; (3) cases of ^ 3 or ~m, and one case of m% giving 

 the formula characteristic of Otocyon. In several instances a con- 

 siderable increase in the size of '^ or m? is found associated with 

 the presence of ^ or m* respectively. An interesting group of 

 cases of extra molars was found in C. cancrivorus, in which this 

 abnormality seems to be common. 



The frequent absence of p l in the Esquimaux dogs is worth 

 notice. Absence of ^ i s common in Dogs, but absence of m?_ is 

 rare. 



In Otocyon one case of m is recorded, and in Icticyon one 

 example has wif instead of m^. 



B. 14 



