396 RHINOCEROS. 



pronounced than in the nickless very open angle of R. Etruscus, but 

 does not form the right angle of R. hemitwchvs. 



7. P.m. 2 is about half worn, and has its anterior barrel much 

 smaller than the posterior, like a compressed conical cup as in Gervais's 

 figure ; there are no accessory plates, but a distinct ring isolated on the 

 base of the crochet. 



8. P.m. 3 is much worn ; the accessory plates are ground away, 

 with only a sinuous outline. 



9. P.m. 4 shows the same characters, but is still more worn. 



10. T.m. 1 is ground down to the cingulum ; the inner termination 

 of the transverse valley shows a ' duck's-head pattern,' as in Gervais' 

 drawings ; the crochet is short and very thick. 



11. T.m. 2 is in the finest condition, only about a third worn ; the 

 posterior valley is not touched behind ; the crochet is thick and forms a 

 nick at its offset, but at an open angle. There is a peculiar twist of the 

 posterior barrel at the apex. The anterior transverse valley has a wide 

 triangular fissure at its central termination ; there are no combing plates, 

 but there is a pillar of enamel rising in the middle of it, evidently given 

 off from the outer ridge. 



12. The last molar, as usual, is triangular, but is little worn ; its 

 anterior barrel is very broad ; the posterior is narrow. There is no 

 rudiment of a posterior valley; the middle valley is triangular, with 

 one large combing plate converging from the outer ridge towards the 

 crochet ; there is also a similar accessory plate sent off from the anterior 

 barrel to overlap the crochet ; the three processes forming three distinct 

 converging intrusions into the outer termination of the transverse valley. 



In the Imola Museum, from near the same locality in which the skvdl 

 was found, but not exactly from the same deposit, there are two rami of 

 a jaw, each portion containing the series of molars from the second pre- 

 molar to the last true molar, beautifully preserved. 



Both rami are fractured anteriorly in a line with the fangs of the 

 second premolar, and they are likewise broken posteriorly in the middle 

 of the ascending ramus. 



The lower margin is perfectly entire, but unfortunately the sym- 

 physial portion and mentary process are missing. 



Dimensions on right side : — 



Length of the last six molars, 8'5 in. Length of the last three true molars 

 measured from the middle of the crowns, 5' in. Ditto of crowns of the three 

 premolars, 3'5 in. Ditto of the last molar, 1*8 in. Ditto of the penultimate, 1'6.5 

 in. Ditto of the antepenultimate, 1'4 in. Ditto of the fourth premolar, T25 in. 

 Ditto of the penultimate premolar, I~l in. Ditto of the antepenultimate premolar, 

 l'Oo in. Height of the jaws between the antepenultimate and penultimate, tip to 

 the alveolar margin, 2-3 in. Height from the middle of the last molar to the 

 alveolar border, 2 - 7 in. 



The crowns of all the teeth are somewhat worn, i.e. the animal was 

 an adult, but not old. Several of the molars of this specimen show the 

 small characteristic bourrelet, which has been indicated by De Christol. 



There is also a third jaw specimen — a left ramus — very well pre- 

 served, in which the molars are less worn than in the two preceding. 

 This specimen is broken vertically in front of the penultimate premolar, 

 and therefore exhibits only the last five molars. 



Length of the last five molars, 8 - 2 in. Ditto ditto of three last true molars, 5'3 

 in. Ditto ditto of two premolars, 2'8 in. 



