No. i.] Allen on Mexican Mammals. 183 



strongly developed (about two inches long and nearly as broad), 

 varying in color, however, from rather pale rufous mixed with 

 gray to deep clear ferrugineous. The rump patch is less strongly 

 colored, less clearly defined, and in two specimens is quite obso- 

 lete. The ventral surface in two specimens is grayish white ; in 

 a third faintly washed with buff ; in a fourth deep yellowish buff ; 

 in a fifth orange rufous, and in the sixth deep orange rufous. 



26. Sciurus cervicalis, sp. nov. 



Sciurus aureogaster leucops ALLEN, Bull. Am. Mus. Nat. Hist., II, Art. XVI, 

 Oct. 21, 1889, p. 166 (excluding synonyms). 



Eight specimens, as follows : Sierra Nevada de Colima, Jalisco, 

 Dec. i-n, 1889, six specimens; Hacienda San Marcos, Volcan 

 de Fuego, Torfila, Jalisco, Dec. 30, 1889, one specimen ; Plains of 

 Colima, Jan. 10, 1890, one specimen. These with four previously 

 received and reported upon (1. c.) form a series of 12 specimens, 

 collected during the months of December, January, April, and 

 May. The series is remarkably uniform as regards coloration, in 

 this respect May and December specimens being indistinguishable, 

 while the range of individual variation is astonishingly narrow, 

 and is covered by the remarks on the four specimens in my former 

 paper on Mexican Mammals (1. c.). 



In comparing the first four examples with a series of Tampico 

 specimens of S. aureogaster I said, "it seems hardly possible that 

 the two forms should be considered as conspecific, the style of 



coloration being so radically different In view, however, of 



former experience in respect to the variability of Mexican Squir- 

 rels, especially in color, it seems probable that Mr. Alston's view 

 that the S. leucops is only a form of S. aureogaster Cuv., occupying 

 a distinct habitat of its own, is correct." 



1 then reluctantly identified this form with 6". leucops, under the 

 name S. aureogaster leucops, noting, however, that it differed from 

 any leucops specimens I had previously examined. I have since 

 (thanks to Mr. Buller's excellent work) received specimens of true 

 leucops from near the type locality, and also additional specimens 

 of aureogaster. This new material shows that not only are leucops 

 and aureogaster very distinct forms, each with its own habitat, 

 but that the specimens from Jalisco then referred to leucops repre- 



