56 PROCEEDIN"GS OF THE NATIONAL. MUSEUM vol. 75 



Although not adult the last-mentioned specimen is indubitably 

 assignable to this species on the characters of temporal fossae, inter- 

 orbital, and third upper molar. An additional detail of importance 

 is the basioccipital, which extends farther ventrad than any part of 

 the bullae. Unfortunately the second specimen is still younger. Al- 

 though belonging to this group it is considerably different, for the 

 pelage is of a delicate maltese gray with no trace of buffy or brown, 

 the infraorbital formina are very smajl, the basioccipital higher in 

 respect to the bullae, and the inner reentrant angles of the molars 

 are deeper. 



The occurrence of so many forms of this genus in the neighborhood 

 of Taochow is very remarkable, but they have trustworthy characters 

 and there is no reason for doubting their validity. 



Family MURIDAE 

 Genus MERIONES lUiger 



MERIONES PSAMMOPHILUS (Milne-Edwards) 



OerMllus psammophilus Milne-Edwaeds, Rech. Mamm., 1871, p. 144 (Mon- 

 golia). 



Specimens. — Twenty-one: Yulinfu, 2, and Yenanfu, Shensi, 6; 5 

 miles south, 6, and 20 miles northwest of Taiyuanfu, 2, and 20 miles 

 west of Ningwufu, Shansi, 5. 



The Shensi example.s average paler and more ochraceous than those 

 from Shansi and it is a question whether the two lots should not be 

 separated. The claws are white, hairs of the unclerparts almost 

 lacking ochraceous bases, and bullae at times touching the zygomatic 

 arches; but the bullae are so little larger than those of unguiculatus 

 that this is a poor character for differentiation. "Wliile Mr. Sowerby 

 was in the Ordos Desert he frequently had opportunity for watching 

 these lively creatures playing about the mouths of their burrows 

 in broad daylight, while elsewhere he has never seen them during the 

 day. They are largely colonial. 



MERIONES UNGUICULATUS (Milne-Edwards) 



GerMlIus unguiculatus Milne-Edwards, Ann. Sci. Nat., vol. 7, 1867, p. 377 

 (Mongolia). 



Specimens. — Two from Tabul, Chihli. 



The claws of this species are black, belly hairs plumbeous at base 

 and with the suggestion of a buffy overwash, and the bullae never 

 touch the zygomatic arches. 



