468 Bulletin American Museum of Natural History. [Vol. XX. 



The largest male skulls have a total length of 96 to 100 

 mm., and a zygomatic breadth of 66 to 73 ; the largest 

 female skulls, 88 to 95 by 58 to 61. 



"BROWN MONKEY (called Mico). The range is almost 

 exactly the same as that of the howler, but the species is 

 rather more common; it is often seen in pairs or bands of 

 three or four. Micos are more active than howlers, taking 

 long leaps from tree to tree; in so doing the tail is used pre- 

 cisely like a fifth hand, clasping the nearest branch when they 

 alight. I have never seen these monkeys swing by their tails, 

 though they sometimes swing by the posterior hands, using 

 the tail as a fulcrum. But, as a rule, monkeys in the forest 

 swing very little; they walk easily on the upper side of a 

 branch, leaping to the nearest branch of the adjoining tree 

 on the line of travel, or sometimes crossing by a vine-stem. 

 They always follow a leader, presumably an old male, and 

 they move after him in single file. Micos are very curious; 

 if a man is passing beneath they stop to look at him, peering 

 down through the foliage. Young ones are easily tamed, but 

 in captivity they are mischievous and often fractious ; gener- 

 ally they become attached to particular persons. Tame ones 

 which we have kept slept all night, and I do not think this 

 species travels after sunset. Micos are esteemed as food by 

 the natives." H. H. S. 



