SIWALIK AND NAEBADA PEOBOSCIDIA. 
99-280 
Third lower true molar. — Three specimens of the last lower molar in the Indian 
Museum exhibit, respectively, fourteen, fifteen, and sixteen ridges. The specimen 
drawn in fig. 12 of Plate VII of the “Pauna Antiqua Sivalensis ” shows seventeen 
or eighteen ridges. 
Ridge-formula. — Prom the above series of teeth, the ridge-formula of the 
molars of E. hysudricus may approximately be represented as follows : — 
ivr AI ? + (5-7) + (7-11) ^ ( 8-12) + (10-12) + (13—17) 
ivx. lU. p (9—11) (10-12) + (12—13) + (14—18) 
Prom the general symmetry of this formula, it is probable that it presents a very 
fair approximation to the truth. It will he found from the table of formula given 
below, that the position assigned to the species from this formula is between 
E. mnaidriensis and E. antiquus, or the second in the list of true elasmodont ele- 
phants : as being a pliocene species this ridge-formula, as being lower than that of 
the pleistocene species (with one exception, which will be referred to again below) 
is in accordance with the theory of evolution, and the less specialization of the older 
forms of a genus. The height of the ridges of the molars of this species is much less 
than in the Indian elephant : the height of the eighth ridge of the last upper molar 
of the former species averaging about 5-| inches, and in the latter upwards of 8 
inches ; the plates of the one are also much thicker than those of the other. 
Species 2 : Eublephas namadicus, Palconer & Cautley. 
The remains of this species of elephant have been obtained only from the Pleis- 
tocene deposits of the Narbada valley, there being no traces of its existence in the 
earlier Siwalik rocks. A considerable number of the true molars are figured in the 
“Eauna Antiqua Sivalensis,” but, with the exception of the last lower milk-molar, 
no complete specimens of the milk-molars are there figured. The collection of the 
Indian Museum unfortunately contains no specimens of the milk-dentition, with the 
exception of the last lower milk-molar ; so that the milk-molar dentition is vir- 
tually still unknown. A second upper true molar in the Indian Museum has twelve 
complete plates. , The specimens in the laiter collection, and those figured in the 
“ Eauna Antiqua Sivalensis,” enable me to make the following approximation to the 
ridge-formula of this species, viz. : — 
Milk-molars. True molars. 
? + ? + ? .P + 12 + 18 
? + ? + (9—10) (i2— 13) + (12—15) + (19—20) 
This ridge-formula will be found to be extremely close to that of the dentition 
of the Em’opean Elephas antiquus, as given by Professor Leith Adams and from 
this resemblance of the ridge-formula, and from the great similarity of the teeth of 
the two species, that writer has come to the conclusion that the Narbada elephant 
is probably a variety of E. amtiquus. With regard to this conclusion, in the first 
'“Dentition and Osteology of Elephas antiquus,” p. 47. Palaeontograph. Soc., 1877. 
