SCIURIDJE-SCIUUDS LEUCOPS. 



755 



Lichtenstein's MS. name hypoxanthus lias of course priority over belli, 

 but seems not to have been published except througli this incidental refer- 

 ence to it by Geoffroy; and indeed there is no proof that the specimens so 

 named were not referable to the true aureogaster of F. Cuvier. 



Dr. Gray's M. griseqflavus and M. leucojis are both described on the 

 same page; and, although griseojlavun stands first, I adopt the name leucops as 

 agreeing better with'the specimens figured and described by Geoffroy, wliile 

 they come also from substantially the same locality; but I at the same time 

 believe gruseoflavus to be specifically the same, notwithstanding the more 

 uniform coloration of the dorsal surface. 



A comparison of Geofiroy's description and figures wi(h tiiose given by 

 Cuvier shows at once the wide differences between them, which Geoffroy 

 himself thus notices : — " En comparant cette description Ji celle de M. 

 Frdddric Cuvier ou h. I'un des individus qui nous sont venus en 1829 et en 

 1831 de la Californie ct du Mexique, on reconnaltra imm''diatement de nom- 

 breuses et remarquables analogies avec ceux-ci, mais aussi de notables diffd- 

 rences. L'lScureuil de la FewMS, en nieme temps qu'il manjue infe'rieurement 

 de la couleur rousse qui serait caractdristiquc pour I'esptce selon les auteurs, 

 plus de roux sur les parties supdrieures ; et cela, non-seulement sur la croupe 

 et la nuque oil le roux domine, mais mCme surledos, otiles polls ont unezone 

 rousse dont d'autres individus ont h peine un vestige. L'ficureuil de la Venus 

 ne devrait-il done pas 6tre considdrd comme une espfcce voisine, niiiis dis- 

 tincte du Sciurus aureogaster ou hi/jwxanfhusf" He refers to the wide ranjrc 

 of individual variation presented bj several well-known species, and is infii"- 

 enced by this in referring- the snscimens collected b^' H'c Venus to Cuvier's 

 (S. aureogaster. 



In size and proportions, there is little difference between the present 

 species and S. aureogaster, but the difference in coloration is so pronounced 

 a'.id of such a character as to leave little doubt of their distinctness. In S. 

 aureogaster, the hairs of the dorsal surface have, in some specimens, a pale 

 central narrow ring of rust, but often the hairs are wholly black beneath the 

 surface and merely narrowly tipped with white. None of the sixteen speci- 

 mens of S. aureogaster before me show any approach to nny of the six 

 specimens of S. leucops, yet ;nore abundant material may show that they are 

 not specifically separable. Among the specimens from Tehuantepec are 

 typical representatives of both forms. 



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