PEROGNATHUS. 97 



Perognathus penicillatus seri Nelson. 



Perognathus penicillatus seri Nelson, Proc. Biol. Soc. Wash., XXV, 

 1912, p. 116. 



Perognathus penicillatus goldmani Towns., Bull. Amer. Mus. Nat. 

 Hist., XXXI, 1912, p. 122 (nee Osgood, N. Am. Fauna, 1900, 

 No. 18, p. 54). 



Type locality. Tiburon Island, Gulf of California, Mexico. 



Genl. Char. Much smaller than P. penicillatus, and without gray 

 tints in the coloring. 



Color. Head and upperparts pale ochraceous-buff lined with black; 

 darkest on lower back and rump; entire underparts and inner side 

 of limbs white; outer side of limbs like upperparts; indistinct deep 

 buff line along flanks; hands and feet white; tail dusky, including 

 pencil, beneath white. Ex type in United States National Museum. 



Measurements. Total length, 171; tail, 90; hind foot, 23. Skull: 

 Occipito-nasal length, 28.4; Hensel, 20; zygoma tic width, 15.3; inter- 

 temporal width, 7 ; length of nasals, 11.9; length of upper molar series, 

 4.1; length of mandible, 12.8; length of lower molar series, 3.8. 

 Ex type in United States National Museum. 



Perognathus penicillatus siccus Osgood. 



Perognathus penicillatus siccus Osgood, Proc. Biol. Soc. Wash., 

 XX, 1907, p. 20. 



Type locality. Ceralbo Island, Lower California. 



Genl. Char. Larger than P. 'p. arenarius, rump bristles rarely 

 present; color dimorphic. Skull large, heavy; mastoids large. 



Color. Upperparts buffy fawn; narrow lateral line pinkish buff; 

 underparts creamy gray phase has upperparts ranging from drab-gray 

 to broccoli-brown. Ex type in United States National Museum. 



Measurements. Total length, 165-187; tail vertebrae, 92-102; 

 hind foot, 23.5-26. Skull: Greatest length, 25.9; basilar length, 

 17.7; mastoid width, 13.8; zygomatic width, 12.6; interorbital con- 

 striction, 6.6; nasals, 8.9; interparietal, 7.2 X 3.6; maxillary tooth- 

 row, 4. Ex type in United States National Museum. 



Perognathus spinatus occultus Nelson. 



Perognathus spinatus occultus Nelson, Proc. Biol. Soc. Wash., XXV, 



1912, p. 116. 

 Perognathus spinatus nelsoni Towns., Bull. Amer. Mus. Nat. Hist., 



XXXI, 1912, p. 122 (nee Merr., Proc. Acad. Nat. Sci. Phila., 



1894, p. 266). 



Type locality. Carmen Island, Gulf of California, Mexico. 

 Genl. Char. Darker than P. spinatus; tail shorter. 



