364 PKOCEEDINGS OF THE ACADEMY OF [1896. 



length, their bases reaching behind the superior prolongation of 

 premaxillaries. Supraorbital frontal processes widely and deeply 

 indented posteriorly, highly and broadh' arched and upraised above 

 the frontal plane. Posterior interorbital constriction tumid, arched 

 high above anterior frontal plane and wider than alveolar length of 

 molar series. Upper anterior incisors rooted at the inferior max- 

 illo-preraaxillary sutures, the termini of incisor roots marked by 

 decided lateral osseous convexities of the rostrum. Incisors broader 

 than deep (transverse exceeds the longitudinal diameter), the ante- 

 rior upper pair each deeply and widely grooved by a single sulcus 

 on the inner face. With the skull, minus mandibles, resting on a 

 pilane, horizontal surface, the chord of the arc described by the ex- 

 posv?d incisors is vertical and the radius of this arc is about one- 

 eight.h (iVo) ^^6 basilar length of skull.^* Lower incisors rootedi 

 anterior to proTI. Incisive foramina reaching to pm. 1 , suddenly 

 broadening and then contracting at base. Palatal bridge longer 

 than width of incisive foramina. Palatal foramina opposite divid- 

 ing alveoJus of second and third premolars. 



For measurements, see table, pages 374, 375, 



General remarks. — As only one specimen of the Baffin Land' 

 Hare, and that consisting merely of head and neck skin with the 

 skull of a j'oung adult animal, has come to hand, it is impossible to 

 furnish a description and measurements of typical adult arcticus, as 

 compared with its southeastern subspecies, bangsi. The descrip- 

 tions of older authors who have handled summer specimens, how- 

 ever, agrees substantially with the above diagnosis. The skull, 

 which was taken from the above mentioned skin by myself, I have 

 considered typical of the form described by Ross, and on this basis 

 rests the separation of the Greenland Hare from arcticus. 



Mr. Ludwig Kumlien, referring to the hares of south Baffin 

 Land, states that " Many do not undergo any change of color dur- 

 ing summer, and I doubt if it be more than a partial change with 

 any. I have seen pure white specimens during all the summer 

 months, and occasionally one about half gray. ""^ In a communica- 

 tion dated Milton, Wis., March 4, 1896, Mr. Kumlien writes me : 

 " I saw no gray hares at any season and I was told at Washington, 

 by Dr. Emil Bessel, that Capt. Hall made [the same] observation 



^*For a comparison between the cranial and external characters ot arcticus 

 and timklus, see Amer. Nat., 1. c, pp. 252, 253. 

 *^ Notes on Mam. of Cumb. Sd., Smiths. Misc. Coll., No. 15, 1879, p. 53. 



