CHAP. IX.] TEETH : MUSTELINE. 231 



;302. C. zebra: all teeth normal except second molars in the upper 

 jaws on each side, which depart from the normal in the following 

 manner. Right »^ 2 has a small extra cusp (Fig. 51, I.) on its outer 

 side, making four instead of three as usual (cp. figure of normal, 

 Fig. 51, II.). The left m? is very extraordinary. It is rather less 

 than twice the size of its fellow of the other side (Fig. 51, 1.). The 

 crown is of an irregularly elliptical form, the long axis being oblique. 

 The posterior and anterior faces are marked by a shallow groove, 

 giving an appearance of imperfect division into two teeth. The total 

 number of cusps is greater than twice that borne by the other, but 

 from the irregularity of the surface it is not possible to speak more 

 precisely. For fear of injury the tooth was not extracted, so that 

 the number of roots cannot be specified. B. M., 82. 5. 26. 1. 



303. H. ichneumon (Egypt), having no right m*- Leyd. Mus. 



MUSTELIDiE 1 . 



The evidence of dental Variation in this family is at present too 

 small in amount to be of much value. It is chiefly interesting in so 

 far as it relates to cases of the occurrence in one genus or sub-family, 

 of a formula characteristic of another. Variations of this class, con- 

 sisting in the presence of or absence of the anterior premolar or last 

 molar, are in some of the forms very common. As will be suggested 

 in the next chapter, some of these, for example, the variations in p l in 

 the Badger, have a certain importance as giving some measure of the 

 magnitude which a tooth may have when the species is, as it were, 

 oscillating between the possession and loss of the tooth in question. 



Amongst Mustelida? there were two cases of supernumerary large 

 premolars, probably reduplicatory. 



Anterior Premolars. 



Mustela (Martens), normally pf, m\. Seen in adult skulls of various species 

 (M. pennanti, martes, foina, zibellina, flavigula, americana), 62: also the following: 

 304 M. foina <j: pi absent both sides. B. M., 1229, k. M. zibellina: p 1 absent 



' both sides from both jaws [perhaps lost], B. M., 58. 5. 8. 189. M. flavigula, 

 Madras, p 1 clearly absent from both jaws, B. M., 79. 11. 21. (521. M. martes? 

 the same. C. S. M., 681. M. melanopus: p 1 absent, probably lost, B. M., 42. 1. 

 19. 100. 



Futorius (Weasels, Stoats, Ferrets and Polecats), normally pf, m£. Seen in 



adult skulls of various species (P. vulgaris, erminea, brasiliensis = xanthogenys, 



foetidus = eversmamii = sarmaticus, lutreola, nudipes, etc.), 105: also the following : 



305. P. erminea: 1. p~i absent, B. M., 43. 5. 27. 11. On the other hand, P. foetidus, 



' B. M., 192 s, has rt. ^T as a two-rooted tooth, standing in a plane at right angles to 



the arcade. 



Gulo : p\, m\. 5 specimens. 



1 Totals of normal skulls refer to Brit. Mus. and Cambridge Mus, only. 



