SIWALIK RHINOCEROTIDiE. 
27 
length is 3 3 inches, and the height of the inner column of the hinder crescent 
1-9 inches. Other specimens of lower jaws in the Indian Museum from the Punjab, 
probably also belonging to the present species, have molars of even still larger 
dimensions. 
Specimen figured in the “ Fauna Antigua Sivalensis .” — In figure 13 of plate 
LXXV of the “ Eauna Antiqua Sivalensis,” a portion of the left ramus of the 
mandible of a rhinoceros from Perim Island is figured under the name of B, {A ?) 
perimensis. This specimen shows the last premolar and the three true molars. In 
the post-humous descriptions of the plates of the “ Eauna Antiqua Sivalensis 5,1 the 
dimensions of the teeth of this specimen are given as follows “ Length of first 
true molar, 1T5 inches ; of second, P4 inches; of third, 1* 5 inches.” Now these 
dimensions exactly correspond with the length of the teeth in the figure ; but at the 
bottom of the plate itself it is stated that all the figures are drawn of half the 
natural size, and I can therefore only come to the conclusion that the dimensions 
of the teeth are really double those given in the description. Hence we shall 
have — 
Length of 1st true molar 2’3 
„ of 2nd „ 2-8 
„ of 3rd „ „ 3'0 
These dimensions are very close to those of the specimens described above, and it, 
therefore, seems probable that the Perim specimen may be rightly referred to 
A. perirnense. There are some signs of a ‘ cingulum ’ being represented in the last 
true molar, but the figure does not show this very clearly. The form of the teeth 
seems to agree very closely with that of the lower teeth figured in this volume. 
Bombay specimen. — Another specimen from Perim Island, belonging to the 
Bombay Branch of the Royal Asiatic Society, and alluded to in the “ Records,” 3 
agrees exactly in dimensions with the above. It consists of the greater part of the 
left ramus and symphysis of the mandible, and shows most of the molar series. 
The broken symphysis exhibits a large incisive alveolus. 
General characters of species. — The foregoing descriptions will have shown that 
Acerotherium perirnense was a very large-sized species of hornless rhinoceros, 
furnished above with one large pair of incisors, and whose upper molar teeth were 
formed after the pattern of those of the Javan and Sumatran rhinoceroses, but which 
presented a less development of the ‘crochet.’ The lower jaw was provided with 
one huge pair of outer incisors, and with the normal complement of molar teeth, 
which were furnished with a distinct ‘ cingulum ’ externally. 
Distribution . — Remains of Acerotherium perirnense have been obtained from 
the ossiferous beds of Perim Island in the Gulf of Cambay, from the lower Manch- 
har beds of Sind, from the Siwaliks of the Punjab, and from the ossiferous beds of 
the valley of the lower Irawadi. No remains of the species have hitherto been 
obtained from the Siwaliks in the neighbourhood of Delira Dun and the Jamna 
1 “ Pal. Mem.,” Vol. I, p. 517. 2 Vol. XIV, p. 156. 
