188 E. Lydelilier — Notes on tlie Dentition 0/ Rhinoceros. [No. 3, 



permanent series of seven molar teetli is very small in both jaws, and is 

 soon shed ;" and again on page 599, " the first milk-molar soon yields 

 place to the first premolar." The above given instances o£ the dentition 

 of It. indicus show that this view cannot be normally correct : the difference 

 in the form of the first upper milk-molar (wi.w.i) and the first premolar 

 {p.m}) shows, in cases where the former tooth persists, that it cannot be 

 a premolar which has supplanted a milk -molar in utero, as might otherwise 

 be the explanation according to Professor Owen's views. 



I now come to the consideration of the non-molar dentition, and shall 

 first treat of the teeth of the upper and secondly of the lower jaw. 



According to Professor Owen,* there is developed, in the foetal skull 

 of R. indicus, immediately behind the maxillo-premaxillary suture, a very 

 small tooth, which, from its position must be the milk-canine : this tooth 

 disappears at an extremely early age, and no permanent successor is ever 

 developed. I can find no record of an upper canine ever having been 

 observed in the foetus of any other species of the genus, and no permanent 

 upper canine occurs in any species. 



In a very young skull of R. indims, figured by Cuvier,t there appear 

 in the premaxilla the alveoli of two teeth, which must be those of the first 

 and second milk-incisors. Two, indeed, appear to be the normal num- 

 ber of upper milk-incisors developed in the genus, though Professor 

 Huxley I speaks of there being three on either side in some species. § 



Normally, in H. indicus there is only one permanent incisor developed, 

 succeeding the first (innermost) milk-incisor ; the former tooth is easily 

 recognized by its lateral elongation. Occasionally, however, as in the skull 

 of which the left upper dentition is represented in fig. 1, a second upper 

 incisor (*.-) is developed, replacing the second milk-incisor. In the figured 

 specimen, the two incisors (i.^, i.") are still in the condition of germs just 

 protruding from their alveoli ; from tlie condition of wear of the molar 

 series it is quite evident that the two incisors belong to the second series, 

 which is also shown by the characteristic form of the innermost (i.^) ; the 

 second incisor (i.^) is not lengthened laterally like the first. In the right 

 premaxilla of the same skull, only the first incisor is developed. Another 

 instance of the development of the second incisor of one side of the upper 

 jaw is afforded by the skull belonging to a mounted skeleton of an old 

 individual of H. indicus in the Indian Museum, in which all the teeth of 

 the permanent series are much worn. In the right premaxilla of that skull 



* ' Odontograph}',' p. 592. 



t 'Ossemens fossiles,' Ed. 1836. Atlas, pi. xliii, fig. 3. 

 J Lou. cit. p. 362. 



J I urn uot aware whicli species is referred to. 



