26 PLEISTOCENE MAMMALIA. 



Dawkins (previous fco 1877), Lydekker (when writing in 1885), Woodward and 

 Sherborn, adopt the above three-fold division of the Pleistocene bears. 



With very few exceptions palaeontologists have considered U. spelseus to be dis- 

 tinct from the rest, but as early as 1844 de Blainville expressed doubts on this 

 head, considering that the differences between the fossil bears were merely racial. 

 Adams too, in 1880 and also in 1881, suggested that the bones attributed to 

 / . spelseus might be only those of larger individuals of the same species as U. ferox i 

 and that all the British fossil bears might be regarded as races of one species. 



Comparison ov the Cave Beak with Beaes of the arctos Type. 

 The following characters have been quoted by various palaeontologists, princi- 

 pally Owen, 1 Busk, 2 and Lydekker, 3 as distinguishing the cave bear from those of 

 the arctos type : 



(a) Distinguishing Characters drawn from the Teeth. 



Cave T.i ';ir. Bears of arctos Type. 



(1) The three anterior premolars of both The three anterior premolars, espe- 

 jaws are generally lost very early, all cially pm. 1 and pm. o of both 

 traces of their alveoli commonly dis- jaws are far more persistent. 

 appearing. 



The complete loss of the three anterior premolars is undoubtedly almost or quite 

 universal in the large cave bear skulls, but is not universal in the case of smaller 

 individuals attributed to the cave bear. Thus Graudry and Boule 4 have shown that 

 in the small race from Gargas pm. 3 is not always lost, and Owen 5 mentions a jaw 

 from Torquay which retains pm. 1. Newton ° too attributes to / '. spelseus a small jaw 

 from the Forest Bed in spite of the retention of pm. 1. 



Cave Bear. Bears of the arctos Type. 



(2) M. 2. has a more or less oblong form, the M. 2 is more constricted behind, and 

 sides being nearly parallel, and the hind the grinding surface of the un- 

 end not much narrower than the middle, worn tooth is more compressed 

 and never or hardly ever pointed. The from side to side than in U. 

 grinding surface when unworn is com- spelasus. Of the three outer cusps 

 paratively flat. On the outer border the two anterior are more nearly 

 are three cusps of which the hindmost equal in size than in U. spelseus 

 is very low and soon worn off (Busk). (Busk). 



1 ' Brit. Foss. Mainm. and Birds,' p. 86, et seq. 

 ' 'Trans. Zool. Soc.,' x, 1*77, p. 60. 



• Palseont. [Mica,' ser. 10, vol. ii, p. 210; and 'Proc. Zool. Soc.,' 1897, pp. 412—426. 

 1 ' Mati'riaux pour I'histoire des temps quaternaires,' p. 100. 

 3 'Brit. Foss. Malum, and Birds,' p. 91. 

 « "WW. of Forest Bed" ('Mom. G-eol. Surv.'), p. 5. 



