380 RHINOCEROS. 



smooth. It certainly does not belong to R. tichorhinus, and the teeth 

 are too large and too broad for the Rhinoceros of the Val d'Arno. It 

 is probably, R. megavhinus, and is an important specimen. The lower 

 jaw is very low for the thickness and size of the teeth. 



Dimensions. — Length of line of six molars, 9-5 in. Length of crowns of the five, 

 8-1 in. Length of three last molars, 56 in. Approximate length of three pre- 

 molars, 4- in. Length of two last premolars, 25 in. Length of crown of penulti- 

 mate true molar, 185 in. Greatest width of ditto, 1-2 in. Length of last molar, 

 2-1 in. Total length of fragment, 145 m. Height of jaw inside at penultimate 

 premolar, 2-5 in. Height of ditto at last molar, 3-8 in. Greatest thickness of jaw 

 below, 2'1 in. 



Another specimen of left side of lower jaw is very like the above, but 

 all the teeth are wanting. 



VIII. Description of Remains of R. Leptorhinus in Museum of 



Nat. History at Turin. 



April, 1861. 



A very beautiful specimen of a right ramus of the lower jaw of a 

 fossil Rhinoceros, marked ' Foss. nei sedimenti fluvio-lacustri pliocenici 

 tra Dusino e S. Paolo (dono dell r Ingegnere Commend. Barbavara),' in a 

 hard mineral condition, weathered grey, containing the whole of the 

 molar series en suite, and part of the symphysis, but the diastemal edge 

 entirely gone ; the horizontal ramus quite entire from the first premolar 

 backwards, but the angle broken off; part of the anterior and basal 

 portion of the ascending ramus present, but the fracture rounded by 

 abrasion. 



The teeth in form, and amount of wear relatively, is nearly a perfect 

 reproduction of Gervais' Montpellier lower jaw (PI. II. fig. 8 of ' Zoolog. 

 Franeaise '), from the first to the last, so much so that the one might be 

 taken for the other. But unfortunately, the Turin specimen wants all 

 the incisive and diastemal portion. The horizontal ramus is very low, 

 as compared with the double lower jaw got in the Mastodon deposit. 

 The posterior boundary of the symphysis is in a line with the posterior 

 third of the penultimate premolar. The lower edge of the ramus is 

 very horizontal from behind on to the premolars. 



The characters of the molars in this specimen are a good deal as in 

 Mr. Gunn's lower jaw. One character of great importance is to be 

 noticed, that on the outside of the penultimate molar, in the furrow 

 between the crescents, there is a very thick layer of cement ; it is only 

 partially present, and probably is dislaminated elsewhere. 



Dimensions. — Length of six molars, 9-5 in. Length of three true molars, 5 - 4in. 

 Length of three premolars, 4-1 in. Length of first premolar, l'2in. Length of 

 second ditto, 1-3 in. Length of last ditto, 1"5 in. Length of antepenultimate true 

 molar (middle of crown), l'6in. Length of penultimate ditto, 17 in. Length of 

 last ditto, 1-95 in. Greatest height of jaw to alveolar edge of last molar, inner side, 

 3-3 in. Height of ditto at first true molar, 275 in. Greatest height at antepenul- 

 timate premolar, 2-4 in. Greatest thickness of jaw, 1 '85 in. Height behind last 

 molar, inner side, 3 - 4 in. 



In the same Museum there is also a penultimate or antepenultimate 

 trueijaolar, upper jaw, left side, of Rhinoceros leptorhinus (merjarhinus). 

 The anterior outer angle is a little broken, but the crochet has the same 

 character as in the Grays Thurrock variety. It is certainly not R. 



