The Weasels of Eastern North America. 17 



north.* Apparently abundant over the whole of this vast region and 

 probably shades into cicognani in the transcontinental forest belt at the 

 south of its range. 



General characters. Largest of the short-tailed American weasels. Tail 

 short (a little more than one-fourth of the total length), tip black, pencil 

 long and bushy ; feet, large and broad ; coat, very long, full, and soft. 



Color. Summer pelage: Upper parts pale yellowish brown, ranging 

 from nearly raw sienna to nearly raw umber and intermediate shades, 

 only a little darker than the upper parts of P. longicauda, under parts 

 varying from primrose yellow to maize yellow ; line of demarkation be 

 tween colors of upper and under parts high up, straight and unbroken. 

 Color of under parts covers under side of arms and hands, inside of legs 

 and toes ; upper lips and chin white ; tail above, same color as back ; 

 below, same color as belly (usually all the way down to the black tip). 

 This yellow under side of the tail is peculiar to this species, so far as I 

 know, and is shown by every specimen except one that I have examined. 

 This one is an adult breeding female (No. 4349, U. S. Nat. Mus.) from Fort 

 Albany, James bay. It has the under side of the tail not yellow, but yet 

 lighter than the upper side. This specimen is the most southerly and 

 easterly example of richardsoni that I have seen and is probably shading 

 toward cicognani. The under fur is the same color as the long hairs. 

 Winter pelage : Pure white all over, often tinged with yellow on the tail, 

 hind quarters, and belly ; end of tail, for a little more than pencil, jet 

 black ; coat extremely long and full ; feet very heavily furred. The 

 change to a white winter coat takes place over the entire range of the 

 species. 



Size. The type, evidently a male, although no sex was given, meas 

 ured : head and body, 11 inches (280 mm.); tail, 4 inches (102 mm.). 

 The only other specimens measured in the flesh are two in the United 

 States National Museum. One of these (No. 5696, from Fort Simpson 

 December 20, 1860, male, Bernard R. Ross) measured : head and body, 

 10.30 inches (261.5 mm.); tail, 4.25 inches (107.5 mm.) ; hind foot, 1.70 

 (43 mm.). The other (No. 2065, " Barren Grounds," June 28, 1864, male, 

 McFarlane) measured: ''extreme length," 13 inches (330 mm.). 



Skull. Skull smooth and light, without pronounced sagittal crest, al 

 though in very old examples there is a slight sagittal development; gen 

 eral shape of brain case, viewed from above, oblong, owing to great breadth 

 across interorbital region and relatively short distance across mastoids ; 

 postorbital processes short, blunt, and not well developed ; audital bullte 

 long and deep and meeting the inflated squamosal in almost a straight 

 line ; inflated squamosal large, much inflated, and almost flush with auditaj 



*On page 149 of Appendix No. IV, vol. II of Ross' Voyage, 8vo, 1819, 

 is a description of a weasel killed at the west side of Baffin's bay. The 

 description is quite minute, and the measurements given are: "From 

 the tip of the nose to the insertion of the tail, eight inches and a half 

 [= 218 mm.] ; to the tip of the tail, eleven inches and a half [= 292 mm.]." 

 The breast and belly are said to be yellow. The sex is not given. 



3 BIOL. Soc. WASH., VOL. X, 1896 



