414 Zoological Society. 



besides the true Bears, only the genera Proci/on, Nasua, Cercoleptes, 

 and Ailurus. I must confess that I cannot concur with him in in- 

 cluding the subfamily Mustelina among the feline family, and at the 

 same time separating the Bears from them as a separate family ; for 

 the course of my observations has convinced me that the Weasels are 

 decidedly more closely allied to the Bears than to any other members 

 of the order. Numerous genera have at various times been one after 

 another abstracted from the Bear-tribe, and added to that of the 

 Weasels, until at length only the four that I have mentioned have 

 remained associated with the Bears. Some remarks in Mr. Water- 

 house's paper seem to imply considerable affinity between the Weasels 

 and the Cats. He observes, " The Cats appear to bear the same 

 relation to the Mustelidce as the Dogs to the Viverrida." This may 

 be, but I should not consider that relation a very close one. He 

 alludes particularly to the straightness of the lower jaw as a common 

 character of the two groups : in the first place, I would remark, that 

 this character is by no means constant among the Weasels ; and 

 secondly, that it is merely a circumstance of form, resulting from other 

 adaptive modifications of the form of the entire cranium, such as the 

 relative length of the jaws, and the development, both in size and 

 number, of the molar teeth. As the posterior termination of the 

 molar series is always on a rather lower level than the glenoid cavity, 

 and as the line of the dental series inclines regularly upwards and 

 forwards, it follows, that for the incisors of the lower jaw to close 

 with those of the upper, the lower jaw must be curved in proportion 

 as the jaws are lengthened. 



Among the characters which I have pointed out in the base of the 

 cranium, it will be seen that the only tangible distinction between 

 the Bears and the Weasels is the presence of the ali- sphenoid canal 

 in the former, and its constant absence in the latter. Much as I 

 have insisted upon the importance of this character as assisting to 

 distinguish groups, I do not consider it sufficient alone to entitle the 

 groups which it separates to the rank of families ; neither am I pre- 

 pared to admit the difference of the teeth sufficient for that purpose, 

 these being, as 1 before observed, merely adaptive modifications. In 

 the true Bears the number of true molars is on each side two above, 

 and three, the full normal number, below. In the Weasels it is only 

 one above and two below. In the subursine group, to which I must 

 add the Bas saris astuta of North America, it is two above and two 

 below ; and among these it is only the Ailurus fulgens, an Indian 

 species, which possesses the ali-sphenoid canal ; while the other four 

 genera, namely Procyon, Nasua, Cercoleptes, and Bassaris, all Ame- 

 rican forms, agree among themselves in possessing the general cha- 

 racters common to the Bears and the Weasels, and in having no 

 ali-sphenoid canal, and two true molars on each side in each jaw. 

 The Bassaris astuta has most usually been placed among the Viver- 

 rine section, in which it also appears in the list published by Mr. 

 Gray ; but doubts have at various times been entertained as to that 

 being its true station. Mr. Waterhouse remarks, in a note appended 

 to the paper from which I have before quoted, " From an examination 



