736 THE POPULAR SCIENCE MONTHLY. 



Again, while much speculation has been had in respect to the 

 origin and use of the mounds of our Western and Southwestern States, 

 it seems to have been overlooked that almost the exact counterparts 

 of these mounds exist to-day in the earth-pyramid of Cholula, near 

 Puebla, and the two pyramids of Teotihuacan, about fifty miles east 

 of the city of Mexico ; and that those structures were in use for 

 religious rites and purposes — i. e., " mound-worship " — at the time of 

 the invasion of the country by the Spaniards under Cortes. It seems 

 difficult, therefore, to avoid also this further inference, that there is an 

 intimate connection as to origin and use between all these North Ameri- 

 can mound-structures, and that they are all the work of substantially 

 one and the same people, who found their last development and, per- 

 haps, origin in Mexico or Central America. In calling attention to 

 these circumstances, and in venturing opinions concerning them, the 

 writer makes no pretension to archoeological knowledge, but he simply 

 offers what seem to him the simple, common-sense conclusions which 

 every observer must come to, who does not bring to his eye a ca- 

 pacity for seeing what has been limited by some preconceived theories. 



EXTERNAL FOEM OF TIIE MAN-LIEIE APES.* 



By EOBEKT IIAETMANN, 

 peofessob in the rniveesity of berlin. 



IN the gorilla, the chimpanzee, and the orang-outang the external 

 form is subject to essential modifications, according to the age 

 and sex. The difference between the sexes is most strongly marked in 

 the gorilla, and these differences are least apparent in the gibbon. 



When a young male gorilla is compared with an aged animal of 

 the same species, we are almost tempted to believe that we have to do 

 with two entirely different creatures. While the young male still dis- 

 plays an evident approximation to the human structure, and develops 

 in its bodily habits the same qualities which generally characterize the 

 short-tailed apes of the Old World, with the exception of the baboon, 

 the aged male is otherwise formed. In the latter case the points of 

 resemblance to the human type are far fewer ; the aged animal has 

 become a gigantic ape, retaining indeed in the structure of his hands 

 and feet the characteristics of the primates, while the protruding head 

 is something between the muzzle of the baboon, the bear, and the boar. 

 Simultaneously with these remarkable alterations of the external struct- 

 ure there occurs a modification of the skeleton. The skull of an aged 

 male gorilla becomes more prognathous, and the incisor teeth have 



* From Anthropoid Apes. By Robert Ilartmann. With Sixty-three Ilhistrations. 

 No. 51, International Scientific Series. New York: D. Applcton & Co., 1886. 



