2 FAUNA ANTIQUA SIVALENSIS. 
extreme degree of ‘pectination’ seen in the molars of any known 
species of elephant.—B.M. 
Length, 11 in. No. of plates, 21. Depth of enamel at tenth plate, 6-2 in. 
Length of space to 10 plates, 43 in. ' 
Fig. 2 a.—Elephas Indicus. Vertical section of an upper penulti- 
mate molar of the existing Indian Elephant. It is composed of 
seventeen ridges, with a reduced talon splent behind, the anterior 
talon being confluent with the first ridge. The anterior eight plates are 
inclined forwards, and by the process of wear they are ground down, so 
that the front part of the tooth is truncated obliquely before the 
posterior lamellae have come into use. The plates are very thin and 
vertical, and the enamel is thin. The gradual attenuation of the plates, 
successively exhibited from /. insignis to LE. Hysudricus, is here carried 
to excess, eighteen being comprised within the space occupied by about 
nine in the equivalent tooth of the African species. The pectinated 
arrangement contrasts strangely with the chevron-formed ridges of 
E.. insignis and the cuneiform plates of H. planifrons. The mass of 
ivory at the base of the tooth is much thinner than in the corres- 
ponding molar of L. Hysudricus. 
Length of crown, 82 in. Space occupied by 10 plates, 44 in. Height at tenth 
plate, 6 in. 
Fig. 2 b.—Elephas Indicus. Vertical section of unusually large spe- 
cimen of last lower molar of an Indian Elephant from Assam, in India 
House collection. The entire length of the crown is about fifteen 
inches, and it includes as many as twenty-seven ridges, of which the 
anterior thirteen are more or less abraded. The first five or six ridges 
incline a little forwards, while the posterior ridges incline so much in an 
opposite direction, that the hindermost are nearly horizontal, producing 
the flabelliform character that so readily distinguishes in most instances 
the last from the penultimate lower molar. The same disposition and 
proportions of the dental substances are observed as in the upper grinder. 
Fig. 3 a.—Elephas Hysudricus, from the Sewalik hills. Vertical 
section of penultimate upper molar, left side. The tooth is in the 
middle stage of wear, eleven of the thirteen plates of which it is 
composed having been in use, and the two anterior ridges being worn 
out. The same vertical disposition of ivory, enamel, and cement is 
presented as in the African Elephant, but the plates are thinner and 
more vertical; the layer of enamel is proportionally thicker; and the 
interspaces occupied by the cement are wider in general than the ivory 
plates. —B.M. 
Length, 7°7 in. Length of 10 plates, 5:75 in. 
Fig. 3 b6.—Elephas Hysudricus. Vertical section of portion of last 
molar of lower jaw, comprising about fifteen plates. The same general 
character, in the disposition and relative proportion of the ivory, 
enamel, and cement are exhibited as in the upper molar, bearing in 
mind that the latter is a younger and consequently smaller tooth. The 
layer of enamel, however, is thinner than in the upper molar. The 
ivory segments curve back near their base, and the apices of the pos- 
terior plates lean towards the front of the tooth, a disposition still more 
marked in the existing Indian Elephant. The dark shade below the 
ivory indicates a core of sandstone, occupying the place of the unossified 
part of the pulp nucleus, and of the undeveloped fangs.—B.M. 
