20 NILS GYLDENSTOLPE, THE SWEDISH ZOOLOG1CAL EXPEDITIONS TO SIAM. 



Skull measurements: 



Greatest length 47,0 & 47,5 mm. 



Condylobasal length 46,0 & 45,0 (47,5 mm. 1 ) 



Zygomatic width 23,6 & 22,0 (25,0 » ) 



Width of brain case 17,8 & 18,2 (19,0 » ) 



Palatilar length 25,8 & 24,5 



Length of bullse 9,5 & 9,5 



Breadth of bulla; 0,0 & 5,8 » 



Maxillary toothrow 17,7 & 17,8 > (18,0 



Tupaia siamensis sp. n. 



<$ Koh Lak, Siamese Malaya, 2C /n 1914. 



This new species is most nearly related to Tupaia malaccana Anders, from the 

 southern parts of the Malay Peninsula, Sumatra and the Linga Island. It may, however, 

 be easily distinguished by its greater size. 



Colour: General colour above grizzled black and russet brown; the hind parts of 

 the body with a well-marked rufescent tinge. Tail much darker than the rest of the upper 

 parts of the body and more coarsely grizzled, the black colour being more predominant. 

 Along the middle of the lower surface of the tail a »snuff brown» area (Dauthenay, Rep. 

 de Couleurs plate 303 and nearest No. 4.) Underparts of the body ochraceous buff, dar- 

 ker on the middle of the abdomen; shoulder stripe påle ochraceous buff, though the stripe 

 is fairly indistinct. 



Skull: Viewed from above the skull resembles that one of Tupaia javanica Horsf. 

 as figured by Anderson (Anat. and Zool. Researches vol. II plate VII. 1878) sa ve that 

 the skull is narrower. The distance between the two lachrymal notches is equal to the 

 distance from that notch to the front of the first upper incisor. 



Extemal measurements of type: 



Head and body = 145 mm.; tail = 175 mm.; hindfoot = 42 mm. 



Skull measurements: 



Greatest length = 44,o; condylobasal length = 41,2; occipitonasal length = 43,o; 

 basilar length = 39,o; length of palate to posterior margin of foramen incisivum = 17,2; 

 lachrymal notch to tip of premaxillare = 17, i; zygomatic breadth = 19,9; greatest 

 breadth of brain case = 17,s; least interorbital breadth = 11, s; length of nasals me- 

 sially = 13,9; breadth of nasals anteriorly = 2,7; breadth of nasals posteriorly .= 4,2; 

 length of bullae = 9,i; maxillary toothrow = 16,2 mm. 



Type: Semiadult male collected near Koh Lak in the Siamese Malaya 26 /u 1914. 



Remarks: As noted in my diary this species was very rare at the localities visited 

 by the Expedition and only a few more specimens were observed. Unlike the other 

 kind of Tupaia which I obtained among the mountains on the boundary to Tenasserim 

 viz. Tupaia belangeri Wagn. this species exclusively seemed to Ii ve on the ground among 

 the undergrowth while Tupaia belangeri Wagn. was most often seen in the trees 

 running about like a squirrel. 



1 Measurements in brackets are tkose of the type ($) according to Thomas. 



