Courtesy, American Museum uj Nalural History 



MYCETES SENICULUS, HOWLING MONKEY ATELES ATER, SPIDER MONKEY 



FIGS. 109 AND 110. DISTAL EXTREMITIES OF PREHENSILE TAILS. 



The rugae in the tails indicate the high degree of sensory specialization in consequence of 

 which these monkeys are able to employ the tail as a "fifth hand." 



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