4-24 FAUNA ANTIQUA SIVALENSIS. 



Fig. 6 h. — Elephas insignis. Vertical section of anterior portion of 

 adult tooth of lower jaw. The two front ridges only have been touched 

 by wear. The ivory, enamel, and cement present the same characters 

 as in the upper molar, but the common curve of the croAvn is slightly 

 concave instead of convex. The posterior part of the basal portion of the 

 pulp nucleus has not completed the stage of calcification, its place being 

 occupied by a nest of calcareous crystals. The figure also shows two 

 ridges of the preceding molar, with their common fang implanted in 

 the lower jaw. — B.M. 



Plate III. 



Fig. 7 a. — Elephas Ganesa, a fossil Indian species. Vertical section 

 of last upper molar. The crown consists of ten principal ridges, with a 

 subordinate talon ridge in front and behind. The anterior seven ridges 

 have their summits worn. A small portion is broken off at the anterior 

 end. Tlie disposition and relative proportions of the ivory, enamel, 

 and cement bear the closest resemblance to those of the corresponding 

 tooth of E. insignis, and the number of ridges agrees. In fact, there are 

 no good cliaracters by whicli the teeth of these two species can be 

 satistactorily distinguished, although the crania are so remarkably 

 different.— B.M. (Reproduced in Plate VI. fig. 1.) 



Length of tootb, 9-25 in. 



Fig. 7 h. — Elephas Ganesa. Vertical section of posterior molar of 

 lower jaw. A small portion of the anterior end of the crown has been 

 broken off, but the presence of the anterior fang proves that the section 

 includes the Avhole length of the tooth, except the first rido-e, the 

 posterior end being entire. It appears to have consisted of eight priu- 

 cijml ridges, with a talon ridge behind, and a subordinate ridge in front. 

 Five of the ridges have been in use, the anterior two being worn down 

 close to the common base of ivory ; the three last ridges are entire. It 

 bears a close resemblance to the corresponding inferior tooth of E. 

 insignis in the form of the ridges, thickiiess of enamel, and proportion 

 of cement. — B.M. 



Y\g. S.~ Mastodon latidens (Clift). Vertical section of two last 

 molars of upper jaw. The specimen of which the section was made 

 was formerly in the collection of the Geological Society, and is figured in 

 Cliffs memoir (Plate XXXVII. fig. 1). The last tooth shows five prin- 

 cipal ridges with a posterior talon ridge and a subordinate ridge in front. 

 The ridges are transverse and divided by a longitudinal cleft into two 

 pairs of principal points without intermediate mammilla; in the hollows. 

 The enamel is very thick and the cement is reduced to a thin layer, 

 only observable in the bottom of the hollows. The ivory lobes resemble 

 those of £^. Ganesa, but are less elevated, with a broader base. The 

 anterior tooth had been a long time in use, and the ridges are nearly all 

 worn out ; they were four in number. Mastodon latidens is the form 

 most nearly allied to E. Cliftii, and, through that species, to the true 

 Elephants. — B.M. (Reproduced in Plate VI. fig. 2.) 



Length of last tooth, 6-5 in. 



Fig. 9. — Mastodon Ohioticus. Vertical section of last upper molar. 

 It consists of four principal ridges and a small talon lobe. The rido-es 

 are transverse, terminating in a trenchant edge ; the ivory seo-ments are 

 in regular angular lobes ; the layer of enamel is of uniform ''thickness 



