34 



NILS GYLDENSTOLPE, THE SWEDISH ZOOLOGICAL EXPEDITIONS TO SIAM. 



Sciurus helgei sp. n. 



Plate VI. Fig. 3—4. 



J* Koh Lak, Siamese Malaya, 29 /ji 1914. — Head and body = 

 42 mm. — £ Koh Lak id /u 1914. — Head and body = 185 mm.; 



: 190 mm.; tail = 

 tail =219 mm. 



228 mm.; hindfoot = 

 hindfoot =42 mm. 



This fine species is nearest related to Sciurus caniceps concolor Blyth. from which 

 it ruay, however, be easily distinguished by its much smaller size and somewhat differing 

 colour. 



Both my specimens were shot on a peninsula a few miles south of Koh Lak, a small 

 town situated at about Lat. N. 11° 45'. The whole peninsula was covered with a very 

 dense vegetation inaking progress very difficult, and the bare rock was only visible at a 

 few places where some limestone mountains raised their ragged peaks against the sky. 

 The vegetation chiefly consisted of a cacté which was found in dense masses along the 

 shores making the landing rather troublesome. Towards the mainland a large area of 

 land was occupied by an impenetrable mangrove swamp and the whole peninsula had 

 years ago probably been an island. A form of a squirrel had then bye and bye been de- 

 veloped. The discovery of this small squirrel is one of the most noteworthy facts met 

 with by the Expedition. Unfortunately only two specimens were collected but the 

 squirrel seemed to be very common and numbers were met with. 



Colour: General colouration above grizzled black and »chamois» (Dauthenay, Rep. 

 de Couleurs. plate 325). Individual hairs on the back black at the base and at the tip 

 and with one or two bands of chamois. Head, crown, hands and feet slaty grey, almost 

 all the hairs with white tips producing a grizzled appearance; legs slaty grey faintly washed 

 with chamois; nose and muzzle white; whiskers black; underparts slaty grey; tail of about 

 the same colour as the back, though perhaps a trifle more yellowish, each hair having 

 4 black annulations and a narrow black tip which gives the tail a banded appearance; 

 tip of tail pure black. 



Skull: The skull may be distinguished from that one of Sciurus caniceps concolor 

 Blyth. by its smaller size and shorter rostrum. The incisive foramina are shorter and 

 narrowing off anteriorly. The nasals are very short but the breadth anteriorly and pos- 

 teriorly does not differ considerably from that of S. c. concolor. 



Type: Adult male collected on the 29th of November 1914 at the neighbourhood 

 of Koh Lak. 



External measurements of type: 



Head and body — 185; tail = 219; hind foot (measured in skin) = 42 mm. 



Another male specimen obtained on the same date and at the same locality measures 

 as follows: head and body =190; tail = 228; hindfoot = 42 mm. 



Skull measurements of type (measurements in parenthesis are those of the other 

 male): 



Greatest length = 50,o (51,o); length from condylus to gnathion = 45,4 (46,i); 

 basicranial length = 42,i (43,o); zygomatic width = 28,o (28,s); width of brain 

 case above roots of zygomata = 23,i (22,8); length of nasals mesially = 14,o (14,2); 



