TRANSACTIONS OF SECTION D. ' ^91 



inner four of the upper jaw when the teeth are met, and are about the same size as 

 these latter, whilst the two upper lateral incisors are larger than the inner two, but 

 are far removed from the canines both in position and size. The comparison of the 

 dentition of the seal with that of the polecat, the grisou, and especially the otter, 

 is instructive. The badger may be said to occupy a place between bears and 

 weasels, and tlie upper incisors have carnivor type, formula, and arrangement. In 

 the upper set the incisors are not embarrassed, although they stand three abreast 

 on each side, as in better marked carnivors. In the badger the intermediates in 

 the lower jaw stand back out of range, as in Putorius and Galictis. In the upper jaw 

 of the otter the incisors are in range, but the second incisors of the lower jaw stand 

 back, as if the teeth were crushed up. It is noteworthy that the first premolar of 

 the upper jaw in this animal is placed internal to the canine, while the first pre- 

 molar of the lower jaw is placed at an interval behind the canine. 



All the molar teeth of the common seal except the first are well known to 

 have two fangs ; as regards the cusps, the precise arrangement is not generally 

 stated. The cusps of the upper molars fit into intervals between the cusps of one 

 lower molar or of separate adjacent molars. The first premolar has a large front 

 cusp with a shoulder (an approach to the formation of a cusp) in front, and a small 

 cusp behind. A slight groove passes forwards and inwards, marking oft" an enamelled 

 surface internal to the cusps. The second upper premolar has a large central cusp, 

 a shoulder in front and to the inner side of this ; and two cusps, one immediately 

 behind the larger and one still farther back. The third premolar has a shoulder 

 in front and internal to a large cusp ; then there are two smaller cusps in succes- 

 sion to this posteriorly. The fourth has a blunter chief cusp, slight irregularities 

 on the inner shoulder, and a second cusp, with an attempt at the formation of a 

 third cusp still farther back ; this tooth is more like the last molar of the otter 

 than the previous teeth are. The molar has a large middle cusp, with a slightly 

 smaller one behind it and a small cusp anteriorly. The Jirst lower premolar has 

 three cusps ; the anterior is the smallest, and the central one next. The cusps are 

 placed near the outer surface of the tooth ; internal to and behind the middle one 

 is an elevation .suggestive of a fourth cusp. The second premolar has a large cen- 

 tral cusp curved somewhat back, a small cusp in front of this, and two behind ; 

 there is a platform internal to the cusps. The third premolar has/o?/)- cusps: the 

 front cusp small, the second the largest and turned back, the two posterior smaller. 

 'ihe fourth premolar has five cusps: two small ones in front of the large one, and 

 two behind it ; the central cusp is bent back. The molar has one cusp in front of 

 and two behind the central cusp, which is not prominent. This tooth is very 

 small, and has a bulging opposite each of the first three cusps. The contrast in 

 the comparison of the incisors of the lion, hytena, and dog with those in the lower 

 jaw of the badger, the polecat, and otter is well worth notmg. In the otter there 

 would not be room for the intermediate (second) incisor to stand in rank. The 

 second incisors in the bear stand somewhat back, but the sockets are placed behind 

 the level of the third pair of incisors. It may seem likely that the habits of the 

 badger and weasel should render a narrow lower jaw desirable anteriorly, but it 

 is not clear that the otter would be well served by the same device. The lower 

 jaw of a very young soal which was examined has lost the lower incisors, but the 

 sockets are suggestive of a nearer approach to the otter arrangement. 



Halichserus grypus has the same dental formula as the common seal. The 

 last molar of the upper jaw is at some distance from the other back teeth, which 

 are all pointed with single cusps. In some, however, there is a shoulder suggestive 

 of a second cusp. This is the case in the last lower, where a slight indication of a 

 cusp exists behind the pointed cone. A furrow is visible on the outer sides of the 

 third and fifth lower and second and fifth upper. The lower canines extend 

 between the upper corner incisors and the upper canines, which are about the same 

 length as the corner incisors, but much thicker. 



The following animals have the intermediate incisor behind the inner and outer, 

 either from base to apex or at the base alone : — Paradoxurus, Ailurus, Her- 

 pestes mungos, Lutra, Galictis, Gulo, Conepatus, Brown Bear, the Malayan 

 Bear, Snow Bejir, Polaf Bear, and Ursus collaris ; MeU^rgus not;, Arctoidotherium 



