A STANDARD EVOLUTION LIBRARY. 



ence and observation in every region of the world,\he work has incorporated 

 with itself each established discovery, and has been modified by every hy- 

 pothesis of value which has been brought to bear upon, or been evolved 

 from, the most recent body of facts. 



XVII. 



Elements Of Geology. A Text-Book for Colleges and for the General 

 Reader. By Joseph Le Conte, LL. D., Professor of Geology and 

 Natural History in the University of California. Revised and en. 

 larged edition. 12mo. With upward of 900 Illustrations. Cloth, $4.00. 



XVIII. 



Animal Life, as affected by the Natural Conditions of Exist- 

 ence. By Karl Semper, Professor of the University of Wiirzburg. 

 With Maps and 100 Woodcuts. 12mo. Cloth, $2.00. 



XIX. 

 Crayfish : An Introduction to the Study of Zoology. Bv Professor T. H, 

 Huxley, F. R. S. With 82 Illustrations. 12mo. Cloth, $1.'75. 



XX. 



Anthropology : An Introduction to the Study of Man and Civilization. 

 By Edward B. Tylor, F. R. S. With 78 Illustrations. 12mo. Cloth, 

 $2.00. 



" The students who read Mr. Tylor's book may congratulate themselves 

 upon having obtained so easy, pleasant, and workman-like an introduction 

 to a fascinating and delightful science." — London Athenaum. 



XXI. 

 First Principles. By Herbert Spencer. Part I. The Unknowable. 

 Part II. The Knowable. 1 vol., 12mo. $2.00. 



XXII. 

 The Principles of Biology. By Herbert Spencer. 2 vols., 12mo. 



$4.00. 



XXIII. 



The Principles of Psychology. By Herbert Spencer. 2 vols., 



12mo. $4.00. 



XXIV. 



The Principles of Sociology. By Herbert Spencer. 12mo. 



2 vols. $4.00. 



XXV. 



The Data of Ethics. Bv Herbert Spencer. Being Part I, Vol. I, 

 of " The Principles of Morality." 12mo. Cloth, $1.25. 



XXVI. 

 Illustrations of Universal Progress. By Herbert Spencer, 

 12mo. Cloth, $2.00. 



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