1174 



MR. R. I. POCOCK ON THE EXTERNAL CHARACTERS 



each side, and there is an upstanding crest on each side of the 

 front of the infranarial poi"tion of the rhinariiim. The rhina- 

 rium is not mesially grooved and the upper lip is not cleft, 

 although the short hairs on each side of the middle line are 

 inclined inwards and downwards in a different direction from 

 those external to them and form a definite crest or fringe. (Text- 

 fig. 40, A, B.) 



The mouth in Sciuridae and Petauristidee is provided with two 

 palatal lobes of hairy integument jutting inwards from the 



Text-figure 39. 



wmI^'"' 



D. 



A. Muzzle of Cynomys ludovicianus, with rliinarium exposed. 



B. „ „ Hatitfa inclica, with vhiuavium partiallj^ hooded. 



C. Mouth and muzzle of 3Iarmota marmota, showing the cheek-lobes 



projecting into mouth, and rhinarium exposed. 



D. Mouth and muzzle of Castor canadensis, half side view, to show mat of 



bristles (m.) inside the cheek. 



cheek. These are capable of meeting over the palate behind 

 the incisor teeth, but they are never fused in the middle line. 

 Two similar but smooth and altogether smaller lingual lobes jut 

 inwards on each side of the tongue. (Text-fig. 39, C.) 



Definite cheek poviches are developed only in three genera — 

 Tcmiias (EiUaonias), Citellus, and Cynomys. I have not been able 

 to examine them in Citellus, but in Tainias and Cynomys they 



