378 RHINOCEROS. 



is ground down very low. There are two fossettes ; that of the posterior 

 valley is a small round hole. The transverse valley is a very contracted 

 fissure at the commencement, terminating in a ' duck's head ' kind of 

 cut de sac. The crochet is short and thick, and given off at a very open 

 angle ; at the ends and inner side of the tooth there is a very thick 

 layer of cement. The crown in amount of wear and pattern (except in 

 the direction of the combing plate) is not unlike the antepenultimate 

 R. hemitoechus (m. 1), in Dinkel's drawing with the six molars*. 

 (See Plate XVI. fig. 1.) 



Dimensions. — Greatest width of crown near ant. fract. at top, 2- in. Greatest 

 ditto behind, at posterior barrel, 1'7 in. Greatest ditto of crown at base, front, 

 2 - 5 in. Greatest ditto behind, 2'5 in. Antero-posterior diameter of crown at top, 

 outer, l'Sin. Antero-posterior diameter of crown at top, inner, 1 '6 in. Antero- 

 posterior diameter of crown in middle, T7 in. Antero-posterior diameter of crown, 

 greatest, l - 8 in. 



The enamel is smooth, the cement is thick, and there is volcanic 

 sand below. 



Lastly, in Signor Ceselli's collection, from Torre di Quinto, there is 

 a detached penultimate right molar, lower jaw, having a disc of pres- 

 sure in front and behind. It agrees exactly in form with the penulti- 

 mate described of Ponzi's jaw fragment (p. 374), but is a trifle larger. 

 It is nearly in same stage of wear. 



Dimensions. — Extreme length, 2 - l in. Width, of front barrel, 1" in. Width of 

 rear barrel, 1/2 in. 



It has a very thick coat of cement between the barrels, which has 

 been rubbed off elsewhere ; this is as thick as in R. hemitoechus. The 

 enamel is smooth, but rather thick. The fangs are present. 



In Signor Ceselli's collection from Ponte Molle there is also a third 

 premolar, lower jaw, right side, well worn. 



Dimensions. — Length of crown, l'-l in. Width in front, - 9 in. Width behind, 

 1-1 in. 



D. In the Museum of the Jesuits' ' Collegia- Romano.' 1 



Examined a very remarkable fragment of the transverse half posterior 

 portion of a last true molar, upper jaw, left side, of a Rhinoceros, in 

 different mineral condition from all the other Roman specimens. It 

 shows a tubercle with four crenatures, attached to the base as in the 

 Montpellier specimen, and the addition to the valley of a combing 

 plate, thick, and pointing at right angles to the crochet; there is also a 

 very distinct intercolumnar tubercle. The disc of the compressed 

 posterior barrel is very well preserved. The enamel is of a bluish grey 

 or lead colour, thin and smooth ; there is some cement outside. The 

 ivory is chestnut-coloured, like the Pignano Elephant ivory ; l the 

 matrix is seen to be a blue clay. The specimen is certainly not from 

 the quaternary volcanic sands of Rome ; its origin is not known. 



The tooth is very much smaller than Ponzi's last molars. 



T)imen i!nn <t In Ponzi "s ^. (p. 372) 



Dimensions. Inches, Inches 



Transverse diameter near base . . . .2-2 2-6 



But for the small size, I would have referred this specimen to R. mega- 

 rhiniis, notwithstanding the combing plate, in consequence of resem- 

 blance of general form, the exact resemblance of the adjjressed basal 



1 See antca, p. 187. — [Ed.] 



