External Characters of the Bears. i>77 



Euarctos, Arcticonus, Helarctos, and Tiremarctos should rank 

 as species or subspecies is a matter about which there will 

 probably be no unanimity for many years to come *. 



In my previous paper upon the bears, only the rliinarimn 

 and feet were discussed. In the present instance I have 

 added a few notes on the ears. 



The Ears. 



I have not examined the ears in Thalarctos, Arcticonus, 

 Melursus, and Tremarctos, but, judging from their size in 

 these genera, it may be assumed provisionally that they 

 resemble the ears of Ursus, Danis, and Euarctos. Taking 

 the ears of these three forms as typical, it may be said that 

 in all bears, except Helarctos, the ears are expanded and 

 flattened distally, with convex margin, and tubular proximally, 

 the angular junction of the tragal and antitragal edges 

 reaching nearly as high as the luw-set supratragus, and the 

 external meatus lying deep at the bottom of the tube. 

 There is no trace of the bursa, an invariable feature in the 

 Canidae and Felidce. 



The supratragus {plica principalis) is a strong ridge 

 overlapped anteriorly by the antero-internal ridge and 

 provided towards its posterior end with a conspicuous knob- 

 like thickening. The tragus and antitragus are small 

 elevations separated by a shallow, narrow notch. The 

 antero-external ridge above the tragus is weak but the 

 antero-internal is strong and prominent where it overlaps 

 the supratragus. The two posterior ridges are likewise, 

 moderately strong, the greater part of the external lying 

 deep in the tubular hollow below the point of junction of. 

 the two rims externally t. 



The ear of Helarctos malayanus (fig. 1, 0) is much shorter 

 and narrower and simpler than in the three above-men liuiud 

 species. The upper portion of the pinna is considerably 

 less expanded and less rigid and its height from the supra- 

 tragus to the summit is less than its total width, despite its 

 narrowness. All the ridges are soft, not rigid, the tragus, 

 the antitragus, and the anterior and posterior ridges are 



* In 1896 Merriam (Proe. Biol. Soc. Wash. x. pp. 65-83) admitted 

 Euarctos, comprising three species, as a subgenus of / r rsus. The rest of 

 tho North American bears, excluding Thalarctos, he referred to Ursus, 

 senstt stricto, recognising two species of the grizzly hear type and three 

 of the brown hear type. 



t The ears of Melursus ursinus and of Helarctos malayanus have been 

 described by Bon s (Die Ohrknorpel, etc., p. 136, 1912) ; but the figure 

 of the ear of M. ursinus is not helpful from my present standpoint. 



Ann. & Mag. N. Hist. Ser. \). Vol. i. 25 



