ME. E. LYDEKKEE 01ST A JAW OF HYOTHEEIUM. 



21 



maxilla of the Sind species (' Pal. Ind.' op. cit. pi. xii. fig. 6), which 

 contains the last two molars in a much worn condition, belongs to a 

 considerably larger animal than the Perim maxilla, the length of 

 the two teeth of the former being 1-45 against 1*29 in the latter ; 

 the talon of m. 3 in the former is also broader and the external 

 cingulum less developed. The smaller Sind upper teeth agree in 

 size with those of the Perim iaw. 



If, then, we agree to confine the name H. sindiense to the larger 

 Sind form, it would appear that the difference in size would be 

 a specific character in the case of the Perim form ; while if, on the 

 other hand, we extend the name H. sindiense to all the Sind speci- 

 mens, the breadth of the lower teeth would likewise point to the 

 specific distinctness of the former. 



Provisionally, therefore, regarding the Perim specimens as distinct 

 from H. sindiense, the form to which they belong may be named 

 H. perimense. This species may be defined as equal in size to 

 H. Waterhousei, but distinguished by its wider molars, in which 

 respect it approaches H. Soemmeringi and H. sindiense, although 

 differing from the former by the greater width of the lower molars, 

 and from the latter either by its inferior size, or by its wider lower 

 molars, or by both these two characters. 



Apart, however, from the minor question of specific distinctness, 

 the occurrence of Hyotherium in the Siwaliks of Perim Island in 

 association with highly specialized ruminants like Bramatherium, 

 Giraffa, and Antelopes of modern African types is of very considerable 

 interest, and is one more instance of that remarkable survival in the 

 East of generic forms long after they had passed away from Europe — 

 a circumstance which was, I believe, first brought to notice by 

 Dr. Blanford. In Europe the genus first appeared in the Quercy 

 phosphorites, was exceedingly abundant in the freshwater beds of 

 St. Gerand-le-Puy, and apparently disappeared after the Middle 

 Miocene of Sansan and Steinheim. 



In India it was apparently abundant in the Lower Siwaliks of 

 Sind, which are certainly not older than the topmost Miocene, and 

 persisted into the Pliocene of Perim, where, however, it appears to 

 have been very rare. The Siwaliks of Perim appear to be probably 

 intermediate in age between the Lower Siwaliks of Sind and the 

 typical Upper Siwaliks of the Eastern Himalaya, since while they 

 contain several older forms like Dinotherium and Mastodon pandi- 

 onis common to the former, they also contain newer types not 

 found in those beds. In the Perim beds Hyotherium and Sus are 

 found associated, although the latter is very common and the former 

 very rare, this association being parallelled by the occurrence of 

 Hipparion and Equus in the Eastern Siwaliks. 



I will conclude this paper with a few remarks on the afiinities of 

 Hyotherium. In the first place, the strongly- marked brachyodontism 

 of the genus, the simple structure of the molars, and the circumstance 

 that the last true molar comes into use at a period when the first 

 tooth of the same series is but slightly worn, at once shows the 

 extremely generalized nature of the genus. In structure the true 



