AND A DENTAL NOTATION. 
489 
phical Transactions for 1801, Home states that “fig. 3 represents the jaw in a still 
more advanced stage of its growth, with the tooth which was only forming in the 
second figure now come to its full size, and in its proper place in the row of teeth : 
there is also a new cell formed for a succeding tooth*.” The original specimen from 
which the figure is taken is preserved in the Hunterian Collection, and it shows that 
the supposed formative cell is one of a series of the medullary cells of the cancellous 
structure of this part of the jaw ; it is itself subdivided into smaller cells, and is not 
a simple cavity like the true cell of a forming tooth. It is also represented of twice 
its natural size in the figure cited, not having been reduced in proportion to the other 
parts of the jaw. 
The latest author on the subject of the dentition of the Phacochoeri, has ascribed 
to that part of their structure a character which would have added a still more re- 
markable anomaly to it, viz. that the last true molar represents both that tooth and 
the penultimate one in the Wild Boar and other herbivorous mammals -I-. 
To this conclusion M. de Blainville was necessarily led by his determination of 
the antecedent teeth. Thus in a Phacochoerus with the dentition answering to that 
represented in figs. 4 and 5 of the present memoir, he regards the teeth marked p 3, 
p 4 and m 1 as belonging to the deciduous series, ‘dents de lait:|;,’ and the rest as be- 
longing to the second dentition ; p 2 being described as a small, speedily lost, false 
molar, m 2 as the first or antepenultimate true molar, and m 3 as the penultimate and 
last true molars, “ already blended together, although not yet protruded from their 
formative alveolus 
With regard to the five teeth in the lower jaw, the first, p 3, is described as the first 
tooth of the second dentition ; the two following, p 4 and w 1, as milk teeth ; the 
fourth, m 2, as the antepenultimate molar of the second dentition, and the last, 3, as 
the penultimate and last molar coalesced. The dentition ascribed to the adult Phaco- 
choerus is that phase which is illustrated in figs. 9 and 10, Plate XXXIV. of the pre- 
4 4 
sent memoir, of which the numerical formula is =14. M. de Blainville, struck 
by the resemblance in the degree of attrition which the molar, m2, presents to the 
antepenultimate molar, m 1, in the adult common Hog, deems them homologous, and 
deduces from that resemblance another argument for the homology of the last great 
molar of the Phacochere with the penultimate and last molars combined of the Hog [j. 
* Philosophical Transactions, 1801, p. 331. 
t Osteographie des Ongulogrades, Hippopotamus and Sus, 4to, 1847. + Ibid. p. 148. § Ibid. p. 148. 
II “ Mais quelle est la signification de cette dent par rapport h ce qui existe chez la sanglier C’est la une 
question qui, malgre son interet, n’a pas meme encore etc soulevee. 
" J’ai cru un moment qu’on pourrait la considerer comme representant les trois arriere-molaires qui se seraient 
soudees de maniere a n’en former qu’une, les trois molaires qui la precedent etant alors celles de remplacement. 
Cette facon de voir dtait surtout appuyee sur la composition de cette dent a la mandibule ou I’on pent voir dans 
les cannelures laterales des separations plus marquees, paraissant indiquer I’antepenultieme, la peuultieme et la 
dernibre avec sou talon. 
“ Mais en rbflechissant sur le caractere serial des espbces de ce genre, il m’a semble que cette opinion devait 
MDCCCL. 3 R 
