I^S SHUFELDT. [Vol. XVII. 



The palatine bones are quite broad ; pars plance of the meseth- 

 moid comparatively short, and are concealed by the palatines 

 when the skull is viewed upon its basal aspect. 



Vomer rudimentary, being developed only as an almost 

 invisible osseous spicula, or, as in the younger individuals, 

 completely unossified. 



The viaxillo-palatines are notably small, and well separated 

 in the median line.^ 



3. Nyctea scandiaca (Linn.), 1766. 



(See Figs, i and 2.) 



The auricular openings, which are without flaps, are, as well as the cra- 

 nium, symmetrical. 



The dermal parts of the auricular openings are of medium 

 size, symmetrical, and situated comparatively low down, as 

 their lower extremities do not pass the superior borders of the 

 mandible, upon either side, and the superior tips ascend only 

 about to the middle of the eye. They are evenly rounded off 

 both above and below, with their longer axes somewhat ob- 

 lique. In an adult male specimen (collected in Ringebo, Oct. 

 19, 1876) the vertical diameter is 20 mm., and the transverse 

 diameter 1 1 mm. There is no evidence of any flap, but the 

 skin on the anterior borders forms, in either case, a somewhat 

 raised fold. The nostrils are quite large, roundish, and placed 

 high. Vertical diameter is 6 mm., and the transverse diameter 

 the same. Posterior to the nostrils, the cere is very little 

 swollen. The craftiuni, which is symmetrical, possesses espe- 

 cially large orbital cavities, and its greatest height is posterior 

 to the latter. 



The beak is of medium length and comparatively strong. 

 The mandibles, not including their horny theca, measured from 

 the frontal bones, will enter slightly more than twice (2.1) into 

 the total length of the cranium. On its superior aspect the 



1 These ossifications are also comparatively small in Micropallas whitneyi, and 

 owing to the relatively as well as absolutely shorter superior mandible in this 

 pygmy species, these spongy masses of bone are brought closer together medi- 

 ally ; indeed, they come very near being in contact. — R. W. S. 



