THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. XV. — Studies of Eocene Mammalia in the Marsh 

 Collection, Peabody Museum ; by J. L. Woetman. 



PAET II. PBIMATES. 



Introduction. 



Somewhat contrary to the accepted order of arrangement 

 usually adopted in treating of the Mammalia, I select next for 

 consideration the Primates, a perfectly natural and homo- 

 geneous order, including the Lemurs, Monkeys, and Apes, as 

 well as Man himself. This latter fact invests the study with 

 more than ordinary importance, inasmuch as any additional 

 evidence bearing upon the past history of the group to which 

 man belongs cannot fail to prove of the highest interest, even 

 though it throw only a side light upon the development of 

 the human kind. In view of the belief that the general current 

 of opinion seems to be setting strongly in the direction of the 

 conclusion that the ancestry of the human species, with all its 

 endowments, both mental and physical, must be sooner or later 

 traced with certainty to this source of origin, we may be 

 pardoned for a somewhat exhaustive presentation of the facts 

 which our fossils exhibit. 



The various groups of Mammalia have been developed and 

 specialized along diverse lines, the primary cause of which we 

 may regard as having been due to adjustment to varying con- 

 ditions of environment. It thus happens that different sets of 

 organs have been involved in these changes, so that when we 

 attempt the classification and definition of a natural group, w T e 

 seek to learn what structures have been most profoundly 

 affected. In the case of the Primates, the enlargement and 

 specialization of the cerebral lobes of the brain constitute the 



A.M. Jour. Sci. — Fourth Series, Vol. XV, No. 87. — March, 1903. 

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