Chapter III 

 TARSIUS SPECTRUM, ITS BRAIN AND BEHAVIOR 



Its Position among the Primates; Measurements and Brain Indices; Surface 

 Appearance oj the Brain; Internal Structure oj the Brain Stem 



TARSIUS occupies a unique position among the primates. It has been 

 singled out by eminent authorities to carry upward the line of 

 human derivation from some lower mammalian form. In this role it 

 deserves closest scrutiny regarding its structure and behavior. 



Appearance and Behaxior of Tarsius 



In size, the animal is about as large as a small squirrel. It is peculiar in 

 appearance because of its closely set, protruding eyes, its long tufted tail, 

 its protruding ears, and the disc-like pads upon the ends of its fingers and 

 toes. 



The tarsiers inhabit some of the Malay Islands. They are noted for two 

 curious habits: they can rotate their heads until they look directly back- 

 wards; and they leap with astonishing speed among the trees from bough to 

 bough in pursuit of insects. Mr. Le Gros Clark has recently given the most 

 detailed description of the tarsier's behavior in captivity. He discusses the 

 affinities of tarsius to lemurs and the insectivores on the one hand, and 

 the anthropoids on the other. In this discussion he recalls the opinion of the 

 Royal Zoological Society of London, previously expressed, to the effect that 

 whatever its definitive allocations, tarsius should be placed in a suborder of 

 primates (Tarsioidca) which is intermediate between L.emuroidca and 



Anthropoidea. 



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