13 



42. The atlas of the Cave Bear (Ursus spelaus). 



42'. The atlas of the White Bear {Ursus maritimus) . This differs from the 

 preceding in the greater relative length and breadth, and squarer form of 

 the transverse processes ; in the greater vertical diameter of the cavities 

 for the occipital condyles ; and in the smaller size of the spinal canal. 

 The odontoid surface is less distinctly marked off from the posterior ar- 

 ticular surfaces than in the Cave Bear. 



43. The vertebra dentata of the Cave Bear {Ursus spelceus). 



43'. The corresponding bone of the White Bear. The superior vertebral 

 laminae or neurapophyses in the Cave Bear have a less relative antero- 

 posterior extent in proportion to their height ; the inferior margin of 

 the transverse process is concave in the Cave Bear, but is convex in the 

 White Bear ; the body of the vertebra projects further behind the base 

 of the transverse process in the Cave than in the White Bear ; the pos- 

 terior oblique processes are turned more outwards in the Cave Bear ; 

 the odontoid process is more convex at its under part ; the anterior part 

 of the spinous process arches further forwards in the Cave Bear. In 

 all the generic characters the dentatse of the recent and extinct species 

 essentially resemble each other. 



44. A lumbar vertebra of the Cave Bear. 



45. A lumbar vertebra of the Cave Bear. 



46. A posterior lumbar vertebra of an old Cave Bear, showing exostosis from 

 the inferior surface of the body. 



47. Some lumbar vertebrae and other bones of the Cave Bear, cemented to- 



gether by a mass of stalactite. 



48. The sacrum of a Cave Bear. 

 48 1 . The sacrum of a Grisly Bear. 



49. The right humerus of the Cave Bear (Ursus spelaus). 



50. The right humerus of the same species of Cave Bear. 



5 1 . The left humerus of apparently the same individual ; this corresponds with 



