1919] Dixon: Bushy-tailed Wood Rats of California 51 



pelage evidently occurs at any time when areas become denuded of 

 hair through accident. This is well illustrated in an adult female 

 (no. 24992) taken September 2, in which a triangular area 20 milli- 

 meters in extent on the rump is thickly covered with a short growth 

 of both underfur and overhair between 3 and 4 mm. long. The position 

 of this spot is such that normally it would be one of the last portions 

 of the body to be invested with the new pelage. No other indication 

 of molt could be discovered in this individual, so the loss of pelage 

 at this particular place was clearly due to accident. 



From an examination of the material at hand, it is apparent that 

 the beginning, progress and termination of molt in Neotowa c. cinera 

 is very similar to that of Peromyscus as described by Osgood (1909, 

 p. 20) and by Collins (1918, pp. 78-79). Stated briefly, the growth 

 of new hair, which is well concealed by the old, begins on the sides 

 and progresses rapidly upwards on each side, meeting at the middle 

 of the back and then inclosing the rest of the body. A small area 

 above the base of the tail and another between the nose and shoulder 

 are the last parts to be clothed with the new hair. (See Collins, 1918, 

 p. 79, figs. 1-3.) The following five specimens have been chosen as 

 best illustrating the time and method of molt in Neotoma cinerea 

 cincr&a. 



No. 24993, $ adult; Bullfrog Lake, 10,600 feet, Fresno County, September 2, 

 1916. No sign of molt; hairs slate gray to base; hairs on tail much worn. 



No. 23112, $ adult; Walker Lake, 8000 feet, Mono County, September 9, 1915. 

 New light buff hairs 5 mm. long on head, shoulders, sides and rump. The new 

 overhairs are entirely black and 8 mm. long. These new hairs are concealed by the 

 longer older hairs and can not be seen until the old hairs are separated and 

 held apart. 



No. 23115, c? adult; Warren Fork, Leevining Creek, 9200 feet. Mono County, 

 September 26, 1915. New hairs on rimip and shoulders 8 mm. long. Tail well 

 covered with new hairs 24 mm. long on sides, and with a thick woolly underfur 

 8 mm. long on top and sides. 



No. 26352, 5 adult; 3 miles east of Jackass Springs, 7200 feet, Panamint Moun- 

 tains, Inyo County; October 8, 1917. Molt complete except on rump and shoulders 

 where a few hairs are still light buff at base. 



No. 26353, c? adult; 3 miles east of Jackass Springs, 7200 feet, Panamint 

 Mountains, Inyo County, October 8, 1917. Molt complete. New hairs slaty gray 

 to base, except for a few hairs on nape which still shoAv buffy at base. 



Color. — General effect, ashy gray. Fresh pelage (adult, Octo- 

 ber 2) : Dorsal surface warm buff, palest on head; back and rump 

 darkened by black tipping of overhairs. Ventral surface, including 

 upper lip, white ; dorsal surface of fore and hind feet white ; ears 

 faintly margined with white (see pi. 3, fig. 6), and scantily covered 

 with grayish and brownish hairs outside, and brownish or blackish 

 hairs inside. 



The pelage on the dorsum consists of two distinct types of hairs : 

 a silky type forming the soft underfur, and coarser, longer, less 

 numerous overhairs, A typical individual hair of the underfur is 

 12 mm. long and usually lacks any black tip although some are of the 

 banded or agouti type with the tip black. The basal portion of such 

 a hair is slate gray and the terminal portion light buff (see fig. B, a). 

 A typical overhair is 22 mm. long and is slate gray at the base and 

 black at the tip (see fig. B, &). A typical hair of the underfur on the 



