538 bulletin: museum of comparative zoology. 



Labrador animal (D. hudsonius). The short median black line, 

 reaching the shoulders in adults, the grayer tint of the summer pelage, 

 the reduction of the postero-internal enamel fold of the anterior 

 two upper teeth and the absence of the antero-external fold in the 

 last lower molar, separate it sharply from the continental forms of 

 rubricatus. Should intergradation be demonstrated, however, rubri- 

 catus and its various forms here recognized, would stand as subspecies 

 of groenlandicus. 



Specimens examined. — Four, as follows: — Greenland, Smith Sound, 

 1, skull only (U. S. N. M.). Ellesmere Land, Bache Peninsula, 2 

 (M. C. Z.). Baffin Land, Cape Mercy, 1 (U. S. N. M.). 



