March, 1904. Mammals of Southern California — Elliot. 303 



hesitate to place the latter name as a synonym of the former, for 

 I cannot perceive the slightest difference, either in external 

 appearance or cranial characters, between them. In the volume 

 of the Proceedings of the Philadelphia Academy for 1893 both 

 names appear, simiolus on page 410, and similis on page 411, 

 thus giving the priority to simiolus. In Miller & Rehn's List it 

 is stated that similis was published on January 27, 1894, and 

 simiolus on Januarv 30, 1894. This, of course, must have hap- 

 pened by the issue of independent leaflets to a few persons, but 

 if one is to abide by the volume issued by the Academy and 

 which is the Official Publication, the name simiolus must take 

 precedence. The species appears to be an abundant one in the 

 localities it frequents, and is found throughout the southern 

 part of the Mohave Desert visited by Mr. Heller, to the vicinity 

 of Daggett, north of which it does not seem to go. for no Dipodo- 

 mys was met with until Ballarat was reached, near Death Valley, 

 where the next race was found. In Mr. Heller's notes of this 

 race, the following account is given: "An abundant anjmal 

 throughout the Colorado and the southern portion of the 

 Mohave Desert, from the lowest valleys to the middle limits of 

 the Upper Sonoran Zone. This is the most abundant and wide- 

 spread mammal of the desert, in which region it forms a large 

 part of the food of the snakes, owls, carnivora, and Indians. In 

 the lowest and hottest valleys it is less common than D. deserti. 

 The burrows, which are few in number, are usually situated in 

 sandy flats or gravelly mesas, often at the bases of spiny or 

 thorny bushes, where they cannot be easily dug out by the 

 larger carnivora. About the eastern end of San Gorgonio Pass 

 they are abundant, but do not extend so far into the pass as the 

 summit, apparently not ranging much farther east than White- 

 water or Cabezon. On the eastern slope of the San Bernardino 

 Range they ascend above 6,000 feet. 



Dipodomys merriami mortivallis. 



Dipodomys m. mortivallis Elliot, Pub. Field Columb. Mus., in, 

 1903, p. 250. Zoology. 



7 Furnace Creek, Death Valley; 1 Ballarat. 



"In Death Valley this form was not abundant, owing appar- 

 ently to the salinity of the soil. Above the valley on gravelly 

 mesas it occurred more commonly, and was also found in the 

 vicinity of Ballarat in Panamint Valley. The range of this race 

 does not seem to overlap that of Perodipus panamintinus , which 



