RHINOCEROS IIEMIT(ECHUS. 329 



processes of the bifid crochet do not project much into the 

 valley. On the other hand, in Bhin. hemitoechus, the ' comb- 

 ing plate ' (p.m. 4 of fig. 1 of PL XVI.) is given off from the 

 middle of the longitudinal or outer ridge, and is directed 

 forwards nearly parallel to the upper lobe of the crochet ; and 

 both these processes jut more into the valley and are more 

 massive. These alleged points of difference may be regarded as 

 minute and fine-drawn, but they have appeared to me to be 

 constant, and to run through the whole series of the molars. 



I do not consider it necessary, on the present occasion, to 

 extend the comparison of the premolars of the Gower Rhino- 

 ceros with those of other species. 



True Molars. — The distinctive characters of the teeth in 

 this species are still more pronounced in the upper true 

 molars. Fig. 3 of PL XVI. represents a detached penul- 

 timate of the left side, in the most favourable stage of wear 

 to show the characters. The posterior valley, not long 

 isolated, forms an irregular triangular pit with sloping walls. 

 The transverse valley at its commencement also forms a 

 triangular fissure with the apex pointing to the sinus between 

 tbe posterior barrel and the crochet ; the valley next bends 

 forward in a sigmoid curve, and is very much contracted by 

 the advance of the crochet towards the anterior barrel ; and 

 it then expands into a rounded cul de sac, the extremity of 

 which points backwards. During the progress of wear the 

 two valleys never form more than two fossettes, in the 

 manner exhibited bym. 1 of fig. 2 (PL XVI.), which presents 

 the antepenultimate or first true molar in a very advanced 

 stage of abrasion. This character, as in the case of the pre- 

 molars, at once distinguishes the molars of Bhin. hemitcechus 

 when found detached from those of Bhin. tichorhinus. 



But the character which best distinguishes them from all 

 other species lies in the peculiar form of the ' crochet,' or 

 promontory projected forward from the posterior colline into 

 the transverse valley. In all the species, fossil or recent, ex- 

 cepting Bhin. hemitoechus, the crochet forms a plate which is 

 emitted at a very open angle with the posterior colline, and 

 directed more or less diagonally towards the anterior outer 

 corner of the crown. This is well seen in the figures given 

 by Cuvier in the ' Ossemens Fossiles.' l PL V. figs. 1, B. C, 

 and PL II. fig. 3, B. of that work exhibit the character 

 in the unicorned Rhinoceros of Java, where the margin of 

 the crochet is continued nearly in a straight line with the 

 anterior margin of the posterior colline. The same is seen 

 in the penultimate B. of fig. 1, PL XVIII., representing the 



1 Ed. 3me. torn. ii. Rhinoceros. — [Ed.] 



