﻿1C PLEISTOCENE MAMMALIA. 



raised into three ill-defined cusps, and an inner somewhat larger portion with a 

 low cusp and a raised inner border. 



Permanent Dentition of the Lower Jaw. — I. 1, 2 and 3 are relatively powerful 

 teeth not differing greatly in size, though i. 3 has the crown somewhat expanded ; 

 i. 2 arises from the jaw at a point behind i. 1 and i. 3. 0. is a powerful tooth 

 with a somewhat prominent cingulum, which often gives off a ridge running along 

 the inner face of the tooth to the apex. Pm. 1 is a small one-rooted tooth with a 

 circular crown. Pm. 2, 3 and 4 are powerful two-rooted teeth increasing pro- 

 gressively in size. The crown is conical, and the apex, central in pm. 4, is further 

 forward in pm. 3 and still further forward in pm. 2. M. 1 is a powerful tooth 

 with a large blade, consisting of two equal-sized trenchant lobes and a small 

 depressed talon. M. 2 is a small tooth with an oval crown not raised into any 

 prominent cusps. 



Meles.— Dental formula — i. f , c. }, pm. -f, m. ^. 



Permanent Dentition of the Upper Jaw. — I. 1 and i. 2 are simple teeth with 

 somewhat chisel-shaped blades, i. 3 is more caniniform. The contrast in size 

 between i. 3 and c. is not so great as in Lutra. Pm. 1 is a very small tooth which 

 almost always falls out at an early period. As a rule its alveolus is completely 

 closed in old animals. Pm. 2 and 3 are simple, conical, two-rooted teeth. Pm. 4, 

 the carnassial, has a prominent blade with a large conical anterior lobe and an ill- 

 defined and often scarcely recognisable posterior lobe. The inner tubercle is 

 large and depressed and not so much anteriorly placed as in Mustela, or so sharply 

 marked off as in Gulo. M. 1 is a very large tooth with a broad surface covered by 

 a series of small tubercles, which rise to form two rather prominent cusps at the 

 antero-external border. This tooth has three roots. 



Permanent Dentition of the Lower Jaw. — The lower incisors are simple teeth of 

 the same character as those in the upper jaw. The canine has a thickened base 

 to the crown, which is somewhat sharply recurved. Pm. 1 is very small, and early 

 falls out ; pm. 2, 3, and 4, are simple conical two-rooted teeth. M. 1 is a long and 

 relatively very large tooth. The anterior half has a rather ill-defined bilobed blade, 

 with a cusp placed internal to the posterior lobe. The posterior half ha s a s ome- 

 what depressed middle portion surrounded by a series of low cusps. M. 2 is a 

 small one-rooted tooth, bearing several slight elevations on the crown. 



Lutra. — Dental formula — i. •§, c. j, pm. -f, m. ^. 



Permanent Dentition of the Upper Jaw. — I. 1 and i. 2 are small cylindrical teeth; 

 i. 3 is somewhat larger and more caniniform, but the canine, which is a rather 

 long and slender tooth, contrasts strongly in point of size with the incisors. Pm. 1 

 is a very small simple tooth, and often falls out early. Pm. 2 and 3 are simple 

 conical two-rooted teeth. Pm. 4, the upper carnassial, has a trenchant blade, with 

 one very prominent principal lobe and a somewhat smaller posterior lobe. The 



