20 FAUNA ANTIQUA SIVALENSIS. 



clay were soft. The fossil Proboscidea are the most striking 

 among the remains. The ordinary Prohoscidea (Dmotherium 

 being regarded as an aberrant form of the same family) 

 may for conyenience be divided into two genera, Mastodon 

 and Elephas ; although the Sewalik fossils show that these 

 so-called genera are indistinguishable throxigh any characters 

 derived from the form and structure of the teeth. There is, 

 indeed, a gradual and continuous passage in the structure of 

 the teeth between the mastodon and elephant, the forms which 

 have been included under the name of Mastodon Elephanto'ides 

 by Clift and one of the Sewalik species constituting the 

 intermediate links. These links are so complete in regard 

 to the development of enamel, ivory, and cement, and the 

 number and form of the dental ridges in the molars, as to 

 break down the technical distinctions founded upon the 

 structure of the teeth which it has been attempted to make 

 between mastodon and elephant. The species of mastodon 

 may be ranged under two sections, viz. : — 



I. Trilophodon, or the mastodon having a ternary formula in 

 the ridges of the intermediate molar teeth. 



II. Tetralophodon, including the species with a quaternary 

 formula. 



Of Trilophodon there are no Indian species yet discovered, 

 the group being at present limited to Europe and America, 

 such as M. giganteus, M. angustidens, and M. Tapiroides. 

 Of Tetralophodon there are three Indian species, viz. M. 

 Sivalensis, M. Perimensis, and 31. latidens (of Clift ex parte). 



Elephas we divide into three sectional groups, viz. : — 



I. Stegodon, being the species which Owen calls Transi- 

 tional mastodons — the M. Elephanto'ides of Clift, and of 

 which there are three, and perhaps four, Indian fossil species, 

 viz. Elephas Cliftii, E. insignis, E. bombifrons, and E. Ganesa. 



II. Loxodon, the species allied to the African elephant, 

 of which we have but one Indian fossil species, viz. E. 

 planifrons. 



III. Elasmodon,^ or the thin-plated Elephants (quoad mo- 

 lars), being the species allied to the mammoth and existing 

 Indian elephant, of which two fossil species are found in 

 India, viz. E. Hysudricus, a huge species with a concave 

 forehead, and E. JSfamadicus, the species from the Nerbudda 

 valley, with the remarkable bulge around the forehead. In 

 all, ten fossil species of mastodon and elephant, as well as a 

 new fossil species of Einotherium, have been found in India. 

 Six of these species have been found in the Sewalik hills. 

 Mastodon Perimensis and Dinotherium Indicum come from 



' Afterwards called Euelephas (See description of plates in Fauna Ant. Siv. 

 Plates 42 to 44).— [Ed.] 



