HHINOCEEOS DECCANENSIS. 
13 
Eh. from Pikermi. 
Eh. crassus. 
anterior and median coUes are stout and broad, and the posterior collis, though 
small, attains the same level as the median. 
From Rh. tichorhinus we must separate Reccanensis^ because of its not 
possessing the thick layer of cement on the molars ; 
because of the absence of the accessary valley “c,” 
and because the grinding surfaces of the molars are not flat as in tichorhinus^ but 
deeply excavated. 
From the hypsodont miocene species from Pikermi, near Athens, described, 
but not named, by Professor A. Gaudry in his splendid 
work — “Animaux Fossiles et Geologic de I’Attique” — 
Rh. Reccanensis differs by its greatly smaller size ; by the position of the guard, 
which is much higher up the side of the tooth than it is in the Pikermi species. 
In the latter the posterior wall of the tooth in premolar 3, molar 1, and molar 2 is 
deeply notched by the posterior valley, which is not the case in Rh. Reccanensis. 
The pliocene American species, Rh. crassus^ Leidy, possesses large incisors 
in the lower jaw, with a broad spatulate symphysis 
strongly resembling Rh. Indicus, while the upper molar 
series is characterized by the presence of four valleys (anterior, two median, and 
posterior). Its specific diversity from Rh. Reccanensis is, therefore, abundantly 
clear. 
The rudimentary character (or possible absence) of the incisors at once sepa- 
rates Rh. Reccanensis from Rh. Indicus^ Sondaieus^ Sumatranus, nasalis, Gray, and 
stemcephaluSi Gray, but there are other distinctions also which will be pointed 
out separately. If I am right in my conclusion that the brachydont type is 
not yet extinct, Rh. Reccanensis would on that ground alone be separated from 
the remaining living Asiatic species (of which the bones are known), namely, Rh. 
Flowerii Gray, and Rh. {ceratorhinus) niger. Gray, as also from the fossil species 
Rh. Sinensis^ Owen ; but there are other distinctions also which require their specific 
separation. 
Taking each species by itself, it will be seen that Rh. Reccanensis differs from 
Rh. Indicus in having only rudimentary (or no) incisors, 
instead of extremely large ones; also by the greater 
development of the guard, by the much greater relative depth of the valleys, and 
the much greater flatness of the outer walls of the upper molars. The rugosities 
at the angle of the mandible, so conspicuous in Rh. Indicus^ are hardly at all 
developed in Rh. Reccanensis, which likewise has not the deep notch on the 
posterior edge of each ramus below the condyle. The broad spatulate extension of 
the symphysis is quite unlike the narrow beak-like form it assumes in Rh. 
Reccanensis. Then the auditory fossa on the squamosal bone is quite unlike, being 
broadly rhomboidal in shape in Reccanensis and much taller and narrower in 
Rh. Indicus. In size Rh. Reccanensis was certainly quite one-fourth less than the 
average Rh. Indicns, if the size of the head offers a sufficient datum to go upon in 
D 
Eh. Indicus. 
