1070 ON A SUPPOSED NEW SPECIES OF NOTOTHERIUM. 



In a third example, No. 5482, tlie hinder half of a horizontal 

 ramus equal as to age with the one last-mentioned, the following 

 individual differences appear — still greater depth, 117 mm. ; 

 increased retrogression of the inlet of the dental canal, and an 

 advance of m^ slightly beyond the root of the coronoid process. A 

 fourth specimen with m'' one-third worn has probably been derived 

 from a middle-aged female; it has the same comparatively slender 

 proportions and rounded extei'nal form as the young adult male, 

 but the teeth are narrower though not shorter, and the dental 

 canal commences much further from the postmolar angle than the 

 length of m-''; the height to the basal ridge of m^ is 84 mm. The 

 tubercles at the entries of the valleys in m^ occur again in a frag- 

 ment with a young tooth of that symbol attached; these tubercles 

 are therefore in the present species occasional, but not, as surmised 

 by Sir R. Owen in the case of N. victorm, constant. Several (six) 

 other more or less mutilated fragments referrible to N. dunense 

 occur in the collection; they do not however enable one to add 

 anything to the record. 



Upper jaw. — In the number of maxillary fossils which very 

 probably belong to one or other of the Nototheridae, there is a 

 series which, without fear of grave objection might be adduced as 

 co-specific with the mandibles above-described. But the seeming 

 absence of irreconcilable characters is not, in this case ?.,t least, 

 sufficient to establish identity, and until the discovery of jaws 

 naturally associated shall remove all the numerous chances of error 

 besetting the exercise of the judgment in such matters, it is as 

 well to avoid the confusion resulting from the misappropriation 

 of any parts of the skeleton. 



EXPLANATION OF PLATE. 



Outer and sideM'iews of the left ramus of the lower jaw of Kototherium. 

 dunense, De V. 



Half natural size.) 



