DESCRIPTION OF THE PLATES. 



35 



sumatranus ; i 1, small mid-incisor; i 2, 

 end of the germ of the large second or 

 outer incisor ; d 2, its deciduous prede- 

 cessor about to fall ; it has been shed on 

 the opposite side ; d 1, two small orifices 

 above the mid-incisors, qu. remains of 

 sockets of deciduous teeth ? Original. 



PLATE 139. 



A section of the crown of the molar of a 

 Rhinoceros, magnified 230 linear diameter : 

 t, obliquely divided ends of the dentinal 

 tubes ; d', peripheral contour of dentinal 

 cells ; d", terminal and intertubular cel- 

 lules ; I, contour lines ; e, enamel. Ori- 

 ginal. 



PLATE 140. 



Fig. 1. Right upper and lower jaws 

 with the teeth and their nerves exposed 

 from the inside, \ nat. size, Hog, (Sus 

 scrofa). Fig. 2. Deciduous and perma- 

 nent teeth of right ramus lower jaw of a 

 young Hog, ^ nat. size, exposed from 

 the inner side. Rousseau. Fig. 3. Skull 

 and teeth of the Barbiroussa, ^ nat. size. 

 Original. Fig. 4. Molar series, right 

 side, upper jaw, nat. size, of an aged 

 Wart-hog (Phacochcerus Pallasii) : the 

 first true molar has been worn out and 

 shed, and the last premolar, p 4, brought 

 into close contiguity with the second true 

 molar, m 2. Original. Fig. 5. Upper 

 molar of the Chceropotamus Cuvieri, nat. 

 size. Fig. 6. Upper molar of the Hyra- 

 cotherium leporinum, nat. size. Fig. 7. 

 Upper molar of the Hippohyus sivalensis, 

 nat. size. Fig. 8. Upper molar of the 

 Merycopotamus, nat. size. Original. 



PLATE 141. 



Fig. 1 . Deciduous and permanent teeth of 



the right side, lower jaw, of a young 

 PhacochtErus JEliani. Original. Fig. 2. 

 The permanent molar series of the adult, 

 showing the worn-out state of the first 

 true molar, m 1, nat. size. Original. 

 Fig. 3. The permanent molar series of 

 an Indian Wild Boar, showing the worn 

 state of the first true molar, m 1, and a 

 supernumerary first premolar, nat. size. 

 Fig. 4. Skull and teeth of a Hippopota- 

 mus, | nat- size. Original. 



PLATE 142. 



Fig. 1. Cut surface; fig. 2, outer sur- 

 face of a longitudinal section of the 

 lower canine tusk of a Hippopotamus, 

 which has been fractured and reunited at 

 * *. Original. Fig. 3. A fossil pre- 

 molar, nat. size, of a Hippopotamus ; 

 one of the three in the portion of jaw in 

 the Woodwardian Museum, which is the 

 original of the figure in ' Scilla, de Cor- 

 poribus Marinis, tab. xn., fig. 1, 1747. 

 Original. 



PLATE 143. 



Fig. 1. Fossil lower jaw and teeth, } nat. 

 size, of a not quite full-grown Hippopo- 

 tamus (Hexaprotodon) from the Sewalik 

 tertiary formations, showing the three 

 incisors on each side of the symphysis, 

 i i, which form its sub-generic character. 

 Fig. 2. Lower jaw and deciduous teeth, 

 \ nat. size, of a very young Hippopota- 

 mus amphibius : i, incisors ; c, canine ; 

 d 1, 2, 3, and 4, deciduous molars ; ml, 

 first true molar. Fig. 3. Unworn crown 

 of a true molar of the Hippopotamus am- 

 phibius, \ nat. size. Fig. 4. The same 

 ground down. Original. 



PLATE 144. 



Figs. 1 to 1 1 show the entire molar series 

 c 2 



