350 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Genus CASTOR Linnseus (1766). 

 Castor LiNNTEUs, Syst. Nat., 12tli ed., 1766, I, p. 78. ** 



The upper molar teeth are subequal, each with one internal and 

 two external enamel-folds; the stomach has a large glandular mass 

 situated to the right of the oesophageal orifice; the anal and urethro- 

 genital orifices open within a common cloaca; the tail is broad, hori- 

 zontally flattened, and naked; and the hind feet are webbed. {Flower 

 and Lydekker. ) 



CASTOR CANADENSIS FRONDATOR Mearnr. 

 BROAD-TAILED BEAVEE; SONORAN BEAVER. 



Cantor canadensis frondator Meaens, Proc. U. S. Nat. Mus., XX, p. 503, Jan. 19, 

 1898, (advance sheet issued Mar. 5, 1897; original description. — Miller and 

 Eeiin, Proc. Best. Soc. Nat. Hist., XXX, No. 1, Dec. 27, 1901, p. 63 (Syst. 

 Results Study N. Am. Mam. to close of 1900). 



[Castor canadensis] frondator, Elliot, Field Col. Mus., Zool. Ser., 11, 1901, p. 116 

 (Synop. Mam. N. Am.). 



Castor clanadensis} frondator, Elliot, Field Col. Mus., Zool. Ser., IV, 1904, pp. 

 159 to 161, fig. 30 (skull of type); fig. 34 (animal). (Mam. Mid. Am. ). 



I'ah-hdne-dh of the Hopi Indians. 



Ap-e'-nd of the Hualapai Indians. 



Type-locality. — San Pedro River, Sonora, Mexico, near Monument 

 No. 98.— (Type, skin and skull. No. UUs, U. S. National Museum.) 



Geographical range. — This form occupies the southern interior area 

 of North America, ranging north from Mexico to Wyoming and Mon- 

 t-ana, its habitat being, of course, restrictedto the vicinity of wooded 

 streams, which it follows through the Austral and Transition zones. 



Description. — Larger than the beaver of Canada, paler and different 

 in coloration, with a much broader tail. Above russet, changing to 

 chocolate on the caudal peduncle above, and to burnt sienna on the " 

 feet; toes reddish chocolate. Below grayish cinnamon, brightening 

 to ferruginous on the under side of the caudal peduncle. Sides wood- 

 brown, enlivened by the tawny olive color of the overhair. Lengjth, 

 1,070 mm.; length of tail, measured from anus, 360; length of bare 

 portion of tail, 125; height of ear from crown, 31; height of ear from 

 anterior base, 3.5; distance from tip of nose to eye, 68; from tip of 

 nose to ear, 12,5; nose to occiput, 165; length of manus, with claw, 

 82; length of pes, with claw, 185. Skull, 133 mm. by 99. Weight, 62 

 pounds avoirdupois. 



Cranial characters. — The skull of the European beaver {Castor 

 flier), which is readily distinguishable from that of the Canadian 

 beaver ( Castor canadensis) by its slender build, lengthened nasal 

 bones, and elongated rostral portion, presents still greater differences 



