14 Bavrjs — The Weasels of Eastern North America. 



The tail is the same color as the upper parts for about half its length, 

 then begins gradually to darken, and is tipped with black ; under fur the 

 same color as long hairs. Winter pelage: The winter pelage is white or 

 brown, according to latitute ; it is white only in the northern part of the 

 animal's range.* In the brown winter pelage the color is usually about 

 the same as in summer, but the coat is, of course, mucli longer and fuller. 

 I have seen a few winter skins that had not turned white, but were much 

 lighter than the usual summer pelage. One of these (No. 2184, collection S. 

 N. Rhoads, Chester county, Penn., December 16, 1S90) has the whole upper 

 parts a beautiful pale drab which fades almost insensibly into the white 

 of the under part. In the white winter pelage the animal is white all 

 over, with generally a yellowish tinge on the posterior half of the upper 

 parts and the whole of the under parts, and wdth a conspicuous black tip 

 to the tail, usually covering about one-third of its length. 



Size. — A^verage of ten adult males from lower Ti-ansition zone : total 

 length, 407 ; tail vertebrse, 1.39.5 ; hind foot, 47. Average of ten adult 

 females from lower Transition zone: total length, 324.5; tail vertebrae, 

 108; hind foot, 34.5. 



SknlL — There is great sexual diffei'ence, in addition to that of size, in the 

 skulls of P. noveboracensis, which seems peculiar to this species. The post- 

 orbital processes are well developed in both sexes. Tlie male skull is 

 large and develops a sagittal crest with age ; the general shape of the brain 

 case, viewed from a1)ove, is less triangular tlian in tlie longicauda group, 

 being not so sharply constricted back of the postorbital processes and 

 rather narrower across the mastoids ; the audital bullfe are large and deep ; 

 the inflated squamosal is much reduced, but usually not quite to the same 

 extent as in the lonaicauda group. The female skull is small and does not 

 develop a sagittal crest ; the general shape of the brain case, viewed from 

 above, is nearly oblong, as in the ridiardsoni group ; the inflated squamosal 

 is large and much inflated and nearly flush wdth the lower surface of the 

 audital bulke ; the audital bulUe and inflated squamosal meet in a round- 

 ing line (in the richardsdni grouj) this line is usually straight). The female 

 skull can be told from that of any of the rlchardsoui group with great cer- 

 tainty by its well developed postorbital processes. 



The dentition is much heavier in the male than in the female, the dif- 

 ference being more marked than in other species. 



Remarks. — P. noveboracensis is very generally distributed over 

 the Atlantic tier of States from North Carolina to New Hamp- 

 shire. It is the only weasel found in the Carolinian zone, but 



* In northern New York and Vermont P. noveboracensis always assumes 

 a wdiite winter coat. In northern Massachusetts it sometimes does. I 

 have two specimens, caught in the same trap at Wayland, Mass., one 

 January 11, 1875, in the white pelage and the other January 12, 1875, in 

 the brown pelage. In central Connecticut it never changes, as shown 

 by large series from Liberty Hill, Conn., taken all through the winter, 

 from October to March. 



