AMPHITHERIUM. 55 
The probability entertained in 1838, and supported by 
the degree of resemblance between Amphitherium and Myr- 
mecobius in the number and form of the molar series of 
teeth, has since been diminished by the discovery of the 
right ramus of a lower jaw, presenting its external sur- 
face to the observer, and the most complete of all the 
extant specimens of the Amphitherium: it is figured, of 
the natural size in outline, and twice the natural size in the 
finished cut, at the head of the present section (fig. 15). 
This jaw, which is in the choice collection of Professor 
Buckland, contains the whole series of twelve molar teeth, 
the last six (m) bemg quinque-cuspidate; the six anterior 
ones (p) unicuspidate, with one or two small basal accessory 
cusps ; it, also, displays the socket of one small canine (J), 
and three small incisors (7), 7 situ ; altogether amounting 
to sixteen teeth on each side of the lower jaw, as indicated 
by the sockets of the second specimen above described. 
The convex condyle, the broad and high coronoid process, 
the projecting angle, the varied kinds and double-rooted 
implantation of the teeth, all unequivocally displayed in this 
fossil, establish the conclusions deduced from the foregoing 
specimens, of the existence of a small insectivorous mammal 
during the oolitic epoch. 
Here, likewise, was a specimen adapted to afford the 
much desired test of the form of the angular process of the 
lower jaw. The inward inflection of this process had been 
long ago pointed out by Cuvier as a character of the genus 
Didelphys, and I have established its generality in the 
entire marsupial series, and pointed out its characteristic 
modifications in the different genera.* 
Dr. Buckland had transmitted this beautiful specimen to 
* Geological Trans. 2nd Series, vol. vi, p. 50. Art. Marsupialia, Todd’s 
Cyclopzedia. 
