ME. W. B. DA.\VKINS ON RHINOCEROS MEGARHESTUS. 413 



TABLE OF MEASUREMENTS. 



Milk Dentition. 

 No. in Cat. Brit. 

 Mus. 



Upper Jaw 1. 

 18755 Dm 1 1-08 

 — 0-86 

 18791 Dm 2 1-35 

 18798 — 1-53 



18791 Dm 3 1-69 

 18755 — 1 6 



18751 Dm 4 186 

 18755 — 1-9 



Lower Jaw 

 27902 Dm 1 085 

 18790 Dm 2 1*22 

 Dm 3 1-65 

 Dm 4 1-8 



Permanent Dentition 

 No. in Cat. Brit. 

 Mus. 



Upper Jaw 1. 



22020 Pm 2 



Pm3 



Pm4 



M 1 



M2 



M3 



18753 c 



1-29 

 1-32 

 1-6 

 1-9 

 2-0 

 2-05 

 2-5 

 21 

 2-35 

 — 21 

 Lower Jaw 

 Pm 2 1-18 



Pm3 



Pm4 



Ml 



M2 



M3 



1-55 

 1 69 

 1-9 

 1-98 

 2-09 



2. 



1-6 



1-41 



2-5 



2-7 



2-76 



2-79 



2-95 



2-65 



2-6 



2-34 



0-61 

 0-93 

 1-14 

 1-28 

 1-39 

 1-28 



3. 



1-8 



1-7 



2-35 



2-27 



2-55 



2-64 



2-46 



2-2 



2-4 



2-25 



0-72 



1-08 



1-42 



1-4 



1-33 



1-28 



§ 6. A minute comparison of the megarliine teeth with thobO of 

 the living species of Ehinoceros proves the truth of Professor 

 Owen's* remark, that each recent species may be identified with 

 absolute certainty by one isolated upper molar. In the fossil species 

 also the maximum amount of specific variation is to be found also 

 in the upper molar series. Choosing the salient characters of the 

 megarhine teeth, we fijid remarkable points both of agreement and 

 difference. 



1. The accessory valley. The anterior combing plate meeting 

 the posterior insulates the accessory from the anterior valley 

 in the fUnicorn Ehinoceros of India, the B. simus (Burchell's 

 Ehinoceros) of South Africa ; and in B. bicornis, true molars one 

 and two being excepted ; while in the B. Sumatranus and B. 

 Javanus the anterior combing plate is undeveloped, and there- 

 fore there is no accessory vaUey defined, as in the leptorhine 

 and megarhine species. 



2. The Colles. The anterior and middle colles taper from the 

 base towards the summit of crown ; and the latter of them is 

 slightly hooked, in the bicorn African, bicorn Sumatran, and 



* Odontography, Article Rhinoceros. 



t Fischer (torn. cit. p. 414 etseq.) and Van der Hoeven (Handbook of Zoology, 

 Vol. ii.) give the synonymy of the various living species of Rhinoceros, to 

 which reference can be made. The names used in the text are those of the cata- 

 logues of the Himterian and British Museums. 



