328 PALEONTOLOGY 



by a space of about half their breadth from the second pre- 

 molar in the lower jaw. The succeeding teeth {p i, z, 3, 4) 

 increase in size to the penultimate molar in the upper, and to 

 the last molar in the lower jaw (p 4, in figs. 95 and 96), 

 which tooth has a third lobe. 



In the last premolar upper jaw (fig. 95, p 4) the cingulum 

 is uninterrupted along the outer side from its anterior well- 

 developed talon (c) to the back part. The two outer cones 

 resemble those of the true molars ; but there is only one inner 

 cone, and the crown of p 4 differs accordingly from that of m 

 1, in being triangular rather than square. A ridge is con- 

 tinued from the interspace between the anterior talon (c), and 

 the outer anterior lobe obliquely inward and backward to the 

 inner lobe, swelling into a small tubercle at the middle of its 

 course. 



The first molar (m 1 ) presents four low thick cones, two 

 internal and two external : each external cone is connected 

 with its opposite internal one by a low ridge, swelling into a 

 tubercle at the middle of its oblique course. The cingulum 

 (cc) seems to be continued uninterruptedly round the crown 

 of this tooth, thickest at the fore and back part, and at the 

 interspace of the inner lobes ; and developing the small acces- 

 sory antero-external tubercle. The second molar (in 2) is 

 similar to, but rather larger than, the first ; the tubercle on 

 the oblique ridge connecting the two front lobes is less 

 developed. The cingulum is obliterated on the inner side of 

 the posterior lobe. 



The last molar is rather narrower behind than m 2; the 

 tubercle on the anterior of the oblique connecting ridges is 

 smaller: that on the posterior ridge is almost obsolete. 



In the last lower premolar (fig. 90, p 4) the division and 

 development of the anterior lobe gives rise to a pair of cones, 

 one external (a), the other internal (/<). connected anteriorly 

 by a basal ridge, in front of which is the fore, part of the 



