OF THE SIVALIK HILLS. 



51 



would establish a species with (in this respect) rather unusual peculiarities. 

 To this smaller species we propose the name of clissimilis, from the differ- 

 ences of form from the rest of the genus. 



From the above additions to the species of the Hippopotamus, and from 

 the marked distinctions in the incisive apparatus of the Hippopotamus 

 Sivalensis, we shall perhaps be justified in at once establishing a new 

 subgenus in this genus of mammalia, fixing the subgeneric characters on 

 the incisive teeth. So marked a distinction in the form, number and 

 character of the incisors will we imagine admit of such an arrangement, 

 with every advantage to science, and in taking this step we place the new 

 subgenus in the following position and order : — 



Genus — Hippopotamus. 

 1st Subgenus — Hexaprotodon. 



1. Species, H. Sivalensis (Nobis.) 



2. „ H. Dissimilis (Nob.) an luc, vel infr^, potius 



referendus ? 

 2m(Z Subgenus — Tetraprotodon. 



1. Species, H. Ampliibius. 



2. H. Antiquus. (Cuv.) fossil. 



3. „ H. Minor (Cuv.) fossil. 



4. „ H. Medius (Cuv,) fossil. 



5. H. Minimus (Cuv.) fossil. 



The specific characters of the first species of our new subgenus being as 

 follows : — 



GcMMs— Hippopotamus. 

 ASitic/emis— Hexaprotodon. 

 >Species— Sivalensis. 



Char. H. dentibus primorihus utrinque sex, subcequalibus ; laniariis difformibus : superioribus 

 nempe quoad sectionem transversalem reniforwibus : inferioribus pyriformibus ; cranio elongato ; 

 oculo ad medium caput fere attingente ; facie ad latera valdv sinuatd. 



Before closing this paper, we may make a few general remarks on the 

 remains of this genus, which, with the exception of the Mastodons and 

 Elephants, are by far the most numerous. 



