SOIURID^-SCIURUS TRPnUOQASTER. 



705 



I hove met wifli no dcscriptiuri published earlier than 18G7 that seems 

 at all applicable to this species. So far as external characters arc concerned, 

 it migiit bo regarded as a subspecies of S. ast'mns, the dilTerenccs being far 

 , less than between either of the subspecies of S. huilsoniun, and ratlier less, or 

 certaiidy not greater, than obtain between S. teduans cBuluani and S. (pstu- 

 ans lu/oniger. It was only the discovery of the presence of two upper pre- 

 molars (the first also large for a Sciurus) that led me to recognize it as 

 specifically distinct from S. astuans. Five of the eight skins of S. tephro- 

 gasler contain the skulls, and in each are two upper premolars. On the other 

 liand, in examining the dentition of some twenty or more specimens of S. 

 astuans, embracing about an equal number of each variety, I have mc< with 

 none having more than a single upper premolar. . , 



The habitat of S. tephrogaster moy be considered as embracing Southern 

 Mexico and Central America, and as extending southward over the northern 

 states of South America to Central New Granada, and probably to Ecuador. 



Taolk LVI. — itauuremcult of $cven ipKinuni of Sciunus TKruiiooAHTER. 



Tadle LVII.— £<«1 of apocinu.'iu txamiiuA of Sciuitus TEPiinoaASTKii. 



