RHINOCEROS ETRUSCUS. 357 



they are vaulted forwards, but not uniformly, as in R. ticlwrhinus ; 

 they are bifid at the apex and then throw down a septum which 

 terminates below in a thick knob (Plate XXVI. fig. 1), and is incom- 

 plete behind {vide ' Dimensions'). The nasal horn is very rough and 

 overlaps the sides of the nasals with an excessively rugous conical 

 raised nucleus ; there are no ramures, as in R. tichorhinus and R. megar- 

 hinus ; the edges of the nasals are thin and arched ; the nasal echancrure 

 is narrow at the bottom, and then arches high forwards, followed below 

 by a rim on either side of the septum. 



6. The zygomatic arches in front are nearly horizontal ; then the 

 posterior part rises upwards in the arch to the glenoid surface, but not 

 nearly so much as in R. megarhinus. (In the detached maxillary and 

 orbitary fragment there is a distinct post-orbital tuberosity defining 

 the orbit behind.) 



7. The temporal fossre are very much as in Cuvier's fig. of R. tichor- 

 hinus, fig. 5, PI. IX. Shin. ; and in the two-horned Sumatra Rhinoceros, 

 fig. 3. 



8. The incisive bones join on to the septum, but are broken. (In 

 the right maxillary specimen, 2 - 2 inches of diasteme remain.) There 

 are no upper incisors apparent, as certainly there are none in the lower 

 jaw. 



9. The orbit is placed mostly above the seventh molar, but its an- 

 terior border advances as far as the middle of the sixth or penultimate 

 molar in the large skull. (In the right maxillary fragment it advances 

 only to the rear part of the sixth molar ; the same remark applies to 

 the skull in two pieces.) 



10. The suborbitary foramen is situated between the third and fourth 

 premolars in the large skull. In the maxillary fragment of the head in 

 two pieces it is over the fourth premolar, close to the nasal echancrure 

 between third and fourth premolars. 



11. The auditory foramen is large and in a line with the upper edge 

 of the zygomatic arches. 



Viewed above, the skull is very like that of R. tichorhinus, but it is 

 not so wide and the nasals are more elongated. The interval also 

 between the orbits is narrower, and the cerebral portion longer. The 

 temporal fossse are of considerable extent ; their bounding edges being 

 less defined than in R. tichorhinus ; they are nearly parallel in the 

 middle, but diverge into the occipital crest behind, and into the orbits 

 in front, as in R. tichorhinus. The frontal tableau is longer and less 

 pronounced ; it is less broad than in R. tichorhinus, but wider than in 

 R. Indicus. There is no hole with ramures to the nasal horn. The 

 occiput is inclined in front with two diverging ridges and a deep de- 

 pression ; but is shelved over by the jsrojecting crest. 



Measurements of the Rhinoceros Skull and Lower Jaw. at Florence. — Skull. — 

 Length of 6 last molars, right side, 8'8 in. Length of 3 last (true) molars, right 

 much worn, 5-0 in. Length of 3 premolars, 4- in. Total length of skull from occipital 

 lateral crest, measured along chord to overhanging tip of nasal, 25'25 in. Total 

 length of ditto from posterior surface of occipital condyle to tip of nasals (vertical 

 plane), 25* in. Total length from nasal echancrure left side to tip of nasals (by 

 callipers), 7*7 in. Total length from nasal echancrure (left) to anterior border 

 of orbit (exactly), 4-5 in. Total length from anterior bonier of right orbit to occi- 

 pital crest (lateral), 14-0 in. Total length from anterior border occipital foramen to 

 palatine echancrure, 12- in. From palatine echancrure to tip of nasals, 12- in. 

 Greatest width across zygomatic arches in line with articular surface, 12 - 7o in. 



