422 CONTRIBUTIONS TO A REVISION OF THE 
mm.; breadth of skull, 99 mm. Maximum length of old males, measured by Dr. 
Mearns, 1130 mm.; of the tail paddle, 285 by 155 mm. 
Remarks. hye Mearns’ comparisons of frondator with canadensis were evidently 
not made with the largest specimens of the latter, as I have examined some whose cra- 
nial and body measurements are about equal to the maximum recorded by him for 
frondator. Nevertheless, there is little doubt that the larger size of average frondator is 
well established. Its long hind foot, broad tail and light coloration distinguish it 
immediately from canadensis. Its approach to pacificus is solely along the line of great 
size as indicated by the length of body and hind foot, but in cranial characters, as also 
in color, it is farthest removed from that race. The close anatomical relation of frondator 
to carolinensis has been mentioned. 
Specimens Examined.—Montana, 1 skin with skull; Wyoming, 1 skull. 
Paciric Beaver. Castor canadensis pacificus, subsp. noy. 
Plate XX Mies Plate ®XOxcd ities 
Type Locality.—Lake Kichelos, Kittitass county, Washington ; altitude about 8000 
feet. Type, No. 1077, ad. 2, in the collection of S. N. Rhoads; collected in April, 
1893, by Allan Rupert. 
Geographic Distribution.—Pacifie slope, of America, from Alaska to California. 
Color.—Above with very uniform, dark and glossy reddish chestnut overhair, 
almost concealing along dorsum the seal-brown underfur. Top of head like back ; sides 
of head, throat, rump, thighs and vent not decidedly lighter than back and belly as in 
the other forms, these parts paling to walnut brown. Ovyerhair of sides and under parts, 
between seal brown and broccoli brown ; under fur of belly drab gray at the roots ; hind 
feet dark seal brown ; fore feet and limbs, dark wood brown. Ears black. 
Anatomical Characters.—Size, largest of the canadensis group, but of more slender 
build, the skeleton throughout being of much greater longitudinal and lesser lateral 
dimensions than in the other forms. Tail and hind foot relatively long. Skull large, 
relatively narrow, with long, narrow rostrum and nasals, the latter with outer margins 
nearly parallel and reaching basally decidedly beyond the premaxillaries. Upper molar 
dentition weak, the crowns of molar teeth rectangular. 
Measurements.—Of the type from carcass: Total length, 1143 mm.; tail vertebre, 
330 mm.; (from relaxed skin) scaly portion of tail, 295 mm. by 122 mm.; hind foot, 185 
mm.; rene th of skull, 142 mm.; breadth of skull, 101 mm.; length of nasals, 53.6 mm.; 
breadth of nasals, 24 mm.; average length and breadth of five skulls from Tacoma and 
Lake Kichelos, Washington, 144 mm. by 99 mm.; average nasal length and breadth of 
same, 04 mm. by 23 mm. 
