2 FAUNA AXTIQUA SIVALEXSIS. 



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, 4| in. 



Fig. 2 a. — Eleplias 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 E. insignis to E. 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 E. planifrons. The mass of 

 ivory at the base of the tooth is much thinner than in the corres- 

 ponding molar of E. Hysudricus. 



Length of crown, 8 - 2 in. Space occupied by 10 plates, 4^ in. Height at tenth 

 plate, 6 in. 



Fig. 2 b. — Eleplias 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 liabelliform 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 rvpper grinder. 



Fig. 8 a. — Eleplias' 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 Avhich 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 b. — Eleplias 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. 



