226 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL.69 



Family CALLITRICHIDAE. Squirrel Monkeys 



The family Callitrichidae includes small squirrel-like monkeys of 

 which the single genus Lcontocebus inhabits Panama. 



Genus LEONTOCEBUS Wagner. Squirrel Monkeys 

 The smallest monkeys of the region are included in the genus 

 Leontocebus. They are little larger than squirrels which they re- 

 semble in form, posture and activity. The general pelage is long 

 and soft, that of the nape and sides especially elongated as a mane, 

 or mantle. The face is thinly clothed with short grayish hairs 

 through which the dark-colored skin is visible to a sharp line of 

 demarcation along the narrow and conspicuous median frontal crest. 

 The hands and feet, with the exception of the great toe, are armed 

 with long, sharp, strongly curved and laterally compressed claws 

 which doubtless facilitate rapid movement. The tail is long, slender 

 and non-prehensile. 



LEONTOCEBUS GEOFFROYI (Pucheran) 



Geoffroy's Squirrel Monkey; Mono titi 



Hapale geoffroyi Pucheran, Rev. Zool., Vol. 8, p. 336, September, 1845. 

 Type from Panama. 1 



Small size, together with the chestnut color of the nape, white fore 

 limbs and frontal crest distinguish the mono titi, as this little monkey 

 is known to natives of the Canal Zone. In western Panama the 

 species is largely or entirely replaced by the similarly small, but 

 otherwise very different animal, Saimiri brstedii, which bears the 

 same local designation. 



In the Canal Zone and at localities visited in eastern Panama, 

 Geoffroy's squirrel monkey seems to be the most abundant repre- 

 sentative of the order, ranging from sea level to at least 2,000 feet 

 altitude on the slopes of the mountains. They were usually met with 

 in troops of four or five, which quickly became alarmed at sight of 

 me and scattered like squirrels, scurrying along the branches and 

 often leaping several feet in passing from tree to tree, giving mean- 

 while rather weak squeaking cries. 



The species has been well known in the Canal Zone for many years. 

 In his list of " Quadrumana found in America north of Panama," 

 Sclater (1872, p. 8) says: " I have recently recorded the receipt by 



1 Locality given by Pucheran in account of Hapale illigeri on same page as 

 that of Hapale geoffroyi. 



