26 The Ottawa Naturalist. [May- 



Bears, Proceedings of the Biological Society of Washington, 

 Vol. ix, pp. 65-82, pis. 4-6, April. 1896. Inthis paper Dr. Merriam 

 gives 440 mm. (17to inches) as the greatest length (front of 

 premaxillary to end of occipital crest), and 277 mm. as the zygo- 

 matic breadth of the largest skull (type of the species) seen by 

 him. Corresponding measurements in A. yukonense are 521 mm. 

 (20 \ inches) and 364 mm., the breadth being proportionally 

 greater in the Yukon skull. 



In general shape the skull of Ursus middendorffi shews much 

 resemblance to that of A. yukonense. The writer has not had 

 the opportunity of studying the dentition of the former species, 

 but if the teeth depart in any particular from the usual Ursus 

 type it would be interesting to note if any approach toward the 

 dentition of Arctotherium is indicated. In U. middendorffi we 

 may have the descendant of A. yukonense, the giant form of the 

 Pleistocene of the extreme north-west. 



The great Cave Bear (Ursus spelceus) was apparently of 

 about the same height and length as the western North American 

 Arctotherium, although the latter animal was probably of heavier 

 build, and its broad, high head with a decidedly short face and 

 nose would give the living animal an appearance quite different 

 from that of the long-nosed U. spelceus. 



The skull of U. spelceus from Gailenreuth, near Muggendorf , 

 Bavaria, figured by Owen in his History of British Fossil Mam- 

 mals and Birds, 1846, has a length (inion to premaxillary) 

 exceeding that of the Gold-run skull by half an inch. In the 

 same publication is a figure of a canine (fig. 29) referred to 

 U. spelceus, from Kent's Hole, Torquay, which is almost as 

 large as the canines of the skull from Gold-run creek. 



Another skull of U. spelceus, from Banwell, England, is, 

 using a corresponding measurement, only one quarter of an inch 

 shorter than the Gold-run skull (Palaeontographical Society, 

 1906, a Monograph of the British Pleistocene Mammalia, Vol. ii., 

 pt. ii., The Bears, by S. H. Reymolds, pi. 1, fig. 1). 



Explanation of Plates. 



Plate I. Right lateral aspect of the skull (type) of Arctother- 

 ium yukonense (upper figure). Occipital aspect of 

 the same (lower figure). 



Plate II. Palatal view of the same skull. 



Plate III. View of the same from above. 



Figures one-fourth natural size, linear. 



