URSUS. 



:ll 



brown Mian in the grizzly bear, but this difference does not always hold, and skulls 

 sometimes show a remarkable amount of variation in this respect. 



Dr. H. Woodward 1 ([notes Dupont as stating that skulls of brown and grizzly 

 bears may be distinguished by the fact that U. arctos has only the last small 

 upper premolar (?. e. pm. 3), while the grizzly has also pm. 1 . Whether this 

 were a true distinction could only be determined by reference to recent skulls, 

 and in these it emphatically does not hold. The following table shows the distri- 

 bution of the small premolar teeth in a- number of bears' skulls, recent and fossil, 

 and it. will be seen that all the recent skulls of the brown bear referred to, 

 show pm. 1 in addition to pm. 3 ; in one case also pm. 2 is present. 















(8) Table showing Development op 



Small Premolars and of Cusps on pm. 4 in Bears 



of the arctos Ttpi 











pm. 1. 



pm. 2. 



pm. 3. 



pm. 1. 



pm. 2. 



pm. 3. 



Cusps on 



pm. 1. 



Cranium and Mandible. 

















U. arctos, Kamtchatka, No. 91.12.18.13 (Brit. 



+ 



+ 



+ 



+ 







No cusps. 



Mus.) 

















U. arctos, Jesso, No. 9G. 4.27.1 (Brit. Mus.) 



+ 





+ 



+ 



One side 





1, 2, 3. 



// arctos var. piscator, N.W. Asia, No. 93.9.10.] 



+ 





+ 



+ 







2 (small). 



(Brit. Mus.) 

















U. arctos, No. 61.4.1.3 (Brit. Mus.) 



Alv. one 

 side 





Alv. 



Alv. 







No cusps. 



U. horribilis, No. 78.6.18.1 (Brit. Mus.) 



+ 





+ 









2 



U. horribilis, No. 58.6.18.10 (Brit. Mus.) 



+ 





One side 



+ 







No cusps. 



II. horribilis var. horrixus, No. 07.2.23.:} 



+ 





+ 



+ 



+ 



+ 



No cusps. 



(Brit. Mus.) 

















U. horribilis, Muggendorf (Brit. Mus.) 



+ 





+ 



+ 







No cusps. 



If. horribilis,' Ballynamore (Brit. Mus.) 



Alv. 



Alv. 



Alv. 











U. hurribilis, Clonburne (Brit. Mus.) 



Alv. 

 Alv. 





Alv. 

 Alv. 











If. horribilis, Ballymahon (Leeds, casl Brit. 



Mus.) 

















U. arctos, 1 Bourn, Lincoln (Mus. Pract. Geol.) 



+ 





+ 



Alv. 









IT. arctos,' Burwell fen (Sedgwick Mus.) 







+ 



+ rt. 

 side 





Alv.'rt. 

 side 



No cusps. 



II. arctos' Manea fen (Sedgwick Mus.) 



Alv. 



, 



■ 











U. arctos 1 (labelled U. spelseus), Crayford, 



Alv. 



Alv. 



+ 











No. M.5()ll (Brit. Mus.) 

















Mandible. 

















U ardos, Manea fen (Fig. Owen, p. 106, fig. 









Alv. 





Alv. 



1 



36a), No. M.231 (Brit. Mus.) 

















II. arctos, St. David's ( Brit. Mus.) 









,, 







No CUSpS. 



Ii. arctos, Gower, No. 859 (Coll. Surgeons Mus.) 















2 (small). 



U. horribilis, Grays, No. 22030 ( Brit. Mus.) ... 















1,3. 



U. horribilis, Deborah Den, No. 40949 (Brit. 













Alv. 



Tooth 



Mus.) 















wanting. 



NOTE.— The position of the small cusps to which the figures 1, 2, 3 in the last column of the above table 

 refer, is indicated in Fig. 6 on PI. VI. In the other columns a + indicates that the tooth is present ; if the tooth 



has been lost, but its socket is present, " Alv." is written. 



1 Figured. 



Geol. Mag.,' viii, 1871, p. 197. 



