NO. 1976. 



TREESHREW8: FAMILY TVPAIID^—LYON. 



135 



Craniul characters. — Rostrum considerably elongated and attenu- 

 ated, so that the distance from the lachrymal notch to the end of 

 premaxilla is equal to the distance from the notch to the occipital 

 condyles. The length 



of the rostrum is mainly 

 brought about by a 

 lengthening of the pre- 

 maxiUary and nasal 

 bones and not by any 

 appreciable increase in 

 length of the maxilla. 

 Fenestra in zygoma 

 large and conspicuous, 

 elongated oval in shape. 

 Dental cTiaracters. — 

 The teeth of Tana do not 

 differ in form or number 

 from those of Tupaia. 

 Owing to the elonga- 

 tion of the rostrum 

 the anterior teeth are 

 somewhat differently 



Fig. 



10.— Tana tana besaea. Type x 1- Cat. No. 142247, 

 U.S.N.M., Kapuas River, Borneo. 



spaced. Thus the lower canine stands closer 

 to the last lower incisor than it does to the 

 adj acent premolar, while in Tupaia it stands 

 midway between the two teeth. The com- 

 bined length of the three upper molars is 

 about one-third the length of the entire up- 

 per tooth row in Tupaia, but in Tana it is 

 distmctly less than one- third the length of 

 entu'e tooth row. 



The absence of a cecum may be one of the 

 generic characters. See page 14. 



Geographic distribution. — The genus Tana 

 so far as known, is confined to the land masses of Borneo and Sumatra 

 and certain of the small adjacent islands. Unlike Tupaia it is not 



Fig. 11.— Upper and lower tooth- 

 rows OF Tana tana besara. 

 Type X 2. Cat. No. 142247, U.S. 

 N.M. Kapuas River, Borneo. 



