THE ALLIES OF THE SQUIRREL: MAMMALIA 425 



possession 'of a relatively larger brain-case and less-developed 

 canine teeth, the adaptation of the vertebral column to an erect 

 posture, the greater length of the lower as compared with the 

 upper extremities, and absence of the power to oppose the 

 great toe to the other toes. Some of these differences seemed 

 to have been bridged over by the discovery in 1891-1892 of 

 the fossil remains of an ape-like -man, or man-like ape (Pithe- 

 canthro'pus erec'tus), from the island of Java. These remains 

 point to the existence of an animal about five and a half feet 

 high, with a skull whose profile is " roughly midway between 

 the skull of a young chimpanzee and the lowest human skull," 

 and whose brain-capacity was nearly equal to that of some 

 savage races of to-day. It is now generally admitted that there 

 is but one species of man in the world (Ho 1 mo sa'piens), and 

 the tendency is to group all the different varieties into three 

 races, the Caucasian of Europe, the Mongolian of Asia, 

 and the Ethiopian of Africa. 



Instinct and Intelligence in Mammals. There are some who 

 ascribe to the birds and to the mammals below man mental 

 attributes, including a power of reasoning, differing from the 

 attributes of man not so much in kind as in degree. Some 

 writers separate man quite distinctly in this regard from 

 the lower animals. Careful observation and experiment with 

 animals under conditions as nearly natural as possible is 

 needed before a final answer can be given to questions which 

 are beset with the same difficulties that we have noted in con- 

 nection with the study of instinct and intelligence in insects. 



In order to test whether dogs and cats exhibit any power 

 of reasoning, Professor Thorndike, of Columbia University, 

 experimented upon these animals by inclosing them when 

 hungry in boxes which could be opened by operating some 

 simple mechanism, such as pulling a wire loop or turning a 

 wooden button. Freedom and food outside were the motives 

 to escape. The experiments showed that in all cases the 



