between the fossil and recent skulls and between the different fossil skulls 

 of the Cave Bears are of the same nature and degree. 



The difference in the proportion of length to breadth which Hunter 

 points out in the skull of the Cave Bear, as compared with that of the old 

 White Bear, which he has placed in juxtaposition with the fossils, is one 

 of the most striking discrepancies between the recent and fossil species ; 

 but it is not the only one. The last molar tooth of the upper jaw in the 

 White Bear has a smaller antero-posterior diameter and a narrower 

 posterior termination as compared with the penultimate molar, than in 

 the Cave Bear. The interspace between the antepenultimate molar and 

 the canine tooth presents the remains of two sockets, one near the molar, 

 the other near the canine, which in younger but full-grown White Bears 

 contain small and simple-fanged premolars. The youngest specimens of 

 the Cave Bear in the present collection exhibit no trace of either of these 

 small premolars, or of their sockets. The posterior palatal foramina are 

 situated opposite the middle of the last molar in all the skulls of the 

 White Bear, but opposite the interspace between the penultimate and 

 last molars in the skulls of the Cave Bear. The zygomatic arches are 

 wider and shorter in the White Bear ; the base of the zygomatic process 

 behind the glenoid cavity is more nearly horizontal in the White Bear, 



The Grisly Bear agrees with the Cave Bear in the great proportional 

 size of the last molar tooth, but the interspace between the antepenulti- 

 mate grinder and the canine is relatively less than in either the Cave 

 Bear or White Bear, and it contains two small and simple premolars in 

 specimens, which from the worn state of the molar teeth have belonged 

 to older individuals than those to which the skulls of the Cave Bear have 

 belonged that present no trace of premolars. 



3. A skull, wanting the lower jaw, of the Great Cave Bear (Ursus spelaus, 

 fcem. ? Ursus arctoideus, Blum, and Cuvier). 



The state of the dentition proves this to have belonged to a young in- 

 dividual ; the enamelled crowns of the canines are relatively smaller than 

 in the. specimens 1 and 2. The form and proportions of the entire skull, 

 of the last molar, and of the edentulous diastema behind the canines, so 



