ATOl'IIVRAX liF.XDIRII. 219 



of the palate to the foramen magnum is, in Scnrx, 44.4 ; in N'cosorcx, 

 43.9. This production of the rostrum is accompanied by a corre- 

 sponding^ increase in tlie len^rth of the under jaw, and shortening- 

 of the distance between the glenoid process and occipital condyle, 

 the ratio of which, to the entire length of the cranium, is 46.3 in 

 Sorcx, and 43.9 in Ncosorcx. In Ncosorcx the distance from the 

 posterior margin of the palate to the front incisor is considerably 

 greater than the distance from the same point to the foramen 

 magnum. In Sorcx the posterior margin of the palate is situate 

 nearly midway between the front incisor and the foramen magnum. 

 On the floor of the cranium, the narrowest part of the basi-occipital 

 is broader in Ncosorcx than in Sorcx. 



Turning, now, to the animal under consideration, and examining 

 it with reference to the points concerned in the above comparison, 

 the fact appears that, while it is in some respects intermediate 

 between the two genera, it also differs widely from both. The 

 rostrum is even longer and more attenuate than in Ncosorcx, with 

 a well-marked angle laterally at its point of union with the cranium. 

 The unicuspid series are nearly parallel. The ratio of the length of 

 rostrum to the entire length of skull is 57.7 ; in Ncosorcx it is 56 ; 

 and in Sorcx 55.5. The ratio to length of skull of the distance 

 from hinder margin of palate to the foramen magnum is 40.8 ; in 

 Ncosorcx 43.9 ; in Sorcx 44.4. (For other ratios see table A, p. 



225.) 



So far as dental characters are concerned it stands alone among 

 the species of the Pacific region. Prof. Baird, in his diagnosis of 

 the genus Ncosorcx, stated that the fourth unicuspid was larger than 

 the third. He further called attention to the circumstance that all 

 the known species of Sorcx from the Pacific Province had the third 

 upper unicuspid decidedly smaller than the fourth.* Twenty )'ears 

 later (in 1877) Dr. Coues thus commented upon this feature : "A 

 striking peculiarity of all the Western species, no matter how diverse 



* Pacific Railroad Reports, Vol. VIII, 1857, p. 13. 



