n8 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XIV. 



In fact they appear so efficient for cutting that their relation to the 

 animal's insectivorous habits is not obvious. Functionally, they are 

 quite as well adapted for cutting vegetation as those of strictly her- 

 bivorous forms and the possibility that they may have passed through 

 a herbivorous or partly herbivorous stage is to be considered. 



LOWER INCISORS. 



The median pair of lower incisors are long, slender, and only slightly 

 curved, merely continuing the inferior outline of the mandibular ramus. 

 They are strongly beveled on the upper side anteriorly and their outer 

 edges are sharp and almost bladelike. They are separated from each 

 other by a considerable space and in this and in the other foregoing 

 respects they are closely similar to the lower incisors in the macropods. 

 Their inner edges are not highly developed for cutting and seem to 

 show a slight tendency to imitate even this character of the macropods. 

 The lower incisors of most phalangers are close-set and decidedly up- 

 curved. Among those examined, the only form showing general resem- 

 blance to C&nolestes is Petauroides. 



Of the small unicuspidate, single-rooted, "intermediate" teeth 

 situated between the terminal incisors and the two-rooted premolars, 

 there are two, and in some cases three, which are to be regarded as 

 incisors. They are indistinguishable by size or shape from the supposed 

 canines and anterior premolars except that the foremost one shows an 

 extreme of pronation which is slightly less pronounced in the succeeding 

 ones. Their crowns are turned forward and lie overlapping each other, 

 the first being in contact with the base of the median incisor and the 

 second with the upper exposed surface of the root of the first. Thus the 

 original apex of each tooth is directed forward and the posterior side of 

 the tooth including a part of the exposed root has come into horizontal 

 position. This arrangement appears to be unique among living mar- 

 supials although slight approaches to it are seen in some of the Phalan- 

 geridae. It is duplicated in every feature, however, in the extinct 

 Patagonian caenolestids. 



CANINES. 



The upper canines in C&nolestes obscurus and apparently in most 

 specimens of C. Juliginosus are simple slender prongs slightly more 

 curved but otherwise similar to the canines of other omnivorous or 

 carnivorous marsupials. In the male they are much more prolonged 

 than in the female, the exposed part measuring 2.5 mm. in a male and 

 only 1.3 mm. in a female. In a specimen of C. fuliginosus figured by 

 Bensley (1903, pi. V, fig. 38) the canine is shown to have a deep lateral 



