Harold S. Crane

“ Three animals from 9-1/2 miles southwest of Pagoda Peak, Rio Blanco County, Colorado, from the drainage of the White River, are intergrades between C. c. concisor and C. c. duchesnei. They are like the latter subspecies in shape and length of the nasals, less expanded distal end of the meatal tube and the rounded angular process, and it appears best, pending the acquisition of more material, to refer them to C. c. duchesnei. ”

“ Comparisons.—From topotypes and near topotypes of Castor canadensis taylori, C. c. rostralis differs as follows: Color: Darker on upper parts owing to darker underfur, guard hairs actually lighter. Skull: Longer; nasals shorter and wider (breadth of nasals averages 54 per cent of length of nasals as opposed to 47 per cent) ; extension of nasals posterior to premaxillae less; rostrum shorter, broader and deeper; dorsal surface of lacrimal bone smaller; zygomatic breadth relative to basilar length greater; mastoid breadth relative to zygomatic breadth less ”

“ Castor canadensis duchesnei new subspecies
Type.—Male, young adult, skin and skull, number 4625, Museum of Zoölogy, University of Utah; Duchesne River, 10 miles northwest of Duchesne, 5,600 ft., Duchesne County, Utah; September 23, 1946; collected by Dave Thomas, original number 160 of K. R. Kelson.
Range.—Drainage of the Duchesne and White rivers in Utah and Colorado.
Diagnosis.—Size large; tail long (see measurements) . Color (type) : Upper parts Sayal Brown, purest on head, grading to Cinnamon Buff at base of tail; underfur Fuscous; hind feet Burnt Umber; ears Fuscous Black ”