QUATEENAET FATHSTA Or GIBEALTAE.. 93 



that it is a second premolar of the left side ( pm. 2 , s). That it is not a milk-molar is 

 shown by the ciixumstance that the opening of the median sulcus does not extend 

 nearly to the bottom of the crown. The existence of an obHque descending ridge on the 

 inner face of the hinder coUiue seems clearly to indicate its relation with the pm. 4 d 

 described above. 



Besides these more perfect teeth, there is (1) a broken fragment of a much-worn 

 upper molar of small size, which, so far as can be judged, probably belonged to the 

 deciduous series ; (2) a mere chip from the inner face of a small much-worn premolar. 



Judging from the apparently different ages or states of wear of these teeth, it is highly 

 probable that they must have belonged to at least two individuals, one of which was 

 much older than the other. 



With respect to the specific characters afforded by the teeth, it may be stated that 

 they seem to correspond in every particular with Dr. Falconer's description of those of 

 Bhinoceros hemitcechus, as will be seen on reference to his account of that species in 

 ' Palffiontological Memoirs,' vol. ii. Without going into needless detail, I may quote 

 what he says on the distinctive characters of the premolars and molar teeth of this 

 species ^. 



He remarks that the premolars of B. hemitoschus may be characterized : — 



1. By the absence of an internal basal " bourrelet ;" 



2. By there being only two fossettes in the worn crown ; 



3. By the middle valley being traversed by the processes of a bifid crochet emitted 

 from the posterior barrel, and by a parallel combing-plate given off by the outer or 

 longitudinal ridge ; 



4. By being invested like the true molars with a very thick coat of cement. 



He proceeds to remark that the absence of a basal " bourrelet," besides other cha- 

 racters, distinguishes the premolars of B. hemitcechus from B. le])torhirms and B. 

 megarhinus. Since B. leptorhinus of Cuvier is synonymous with B. megarhinus of 

 Christol, and B. le])torMnus of Owen with B. hemitcechus, Falc, it is not quite clear 

 what his meaning is in the expression just quoted. But, as partly explanatory of it, 

 I may cite a note of his, made in the British Museum in June 1864, with reference to 

 a tooth numbered 36770, which runs thus : — " A true right from Peckham, exactly in 

 the same stage of wear of crochet and outer ridge as the Gibraltar molar ; and the ter- 

 mination of the transverse valley, as in it, is a triangular fissure without complication. 

 It has no basal ' bourrelet.' It is probably m. 1 , like the Gibraltar tooth ; and the two 

 are of nearly the same size. It has no combing-plate." Dr. Falconer, in a side-note, 

 says that this tooth " ought to be figured with the Gibraltar bone," thus marking 

 emphatically, what I know was his opinion, that the two teeth were specifically 

 identical ; and his recommendation as to the giving of a figure of the Peckham tooth 

 should have been obeyed, had the necessity for it not have been obviated by the 



' Op. cit. p. 328, pis. xvi., xvii. &c. 



VOL. X. — PART II. No. 6. — August 1st, 1877. o 



