A BOAR PECCARY, SHOT WHEN FLEEING BEFORE A JAGUAR: GATUN BAKE 



(see page 175) 



mals, there are other vertebrates, includ- 

 ing certain nocturnal birds, reptiles, and 

 fish, that have brilliant eyes at night, as 

 is the case with some of the inverte- 

 brates, such as spiders, beetles, and crabs. 



Unquestionably the function of the 

 tapetum is to give increased keenness to 

 the night vision, for in no instance do 

 strictly diurnal creatures have reflecting 

 eyes, while practically all those of noc- 

 turnal habits possess this element of the 

 eye. 



On the Panama trip considerable study 

 was given this subject, for there were 

 missing links that only the tropics could 



supply. Up to this time I had not found 

 a single member of the Primates that had 

 reflecting eyes, for all tested were diurnal, 

 like man. In several countries there are 

 species of nocturnal monkeys, but I could 

 never find one in the zoological collec- 

 tions, and therefore it was with great in- 

 terest that I tested the eyes of the little 

 owl monkey, whose rescue from a flooded 

 forest is mentioned elsewhere. 



Selecting a dark night and turning the 

 lantern toward it as it sat on the upper 

 edge of a porch, its eyes glistened like 

 two brilliant diamonds. 



Later, on taking a flashlight picture of 



i73 



