Agassiz and His Works. 



213 



simple and some hopelessly complex, just as are the 

 familiar workings of the human mind. Not only is 

 his erudition throughout remarkable, but his grasp 

 of facts, intricate in their relations and numerous, is 

 quite amazing. In nothing is this better exhibited 

 than in his celebrated demonstration of the corre- 

 spondence of embryological, geological, and zoo- 

 logical succession. He shows that, in many orders, 

 the species which first appear in the older beds re- 

 semble the embryo of the highest species now living ; 

 and, moreover, that this fossil and this embryo have 

 characters in common with the living species that 

 stand lower in the zoological scale. Thus among 

 Crustacea the living Brachyurans stand highest ; but 

 the embryo of the Brachyuran has a long tail like 

 the Mactourans, which are characteristic of the 

 middle geological periods, and among the living are 

 zoologically inferior to the Brachyurans. 



Among the works of Agassiz that have been widely 

 circulated and extremely popular, is his Geological 

 Sketches, issued in 1866. This little volume was the 

 result of notes made for extemporaneous lectures, 

 and appeared finally as a series of articles in the 

 Atlantic Monthly. There are ten chapters on topics 

 of especial interest, as The Growth of Continents,'' 

 The Formation of Glaciers,'' Mountains and their 

 Origin," and others. 



Equally valuable is a work previously referred to, 

 The Structure of Animal Life, which was issued in 

 the same year, and comprised six lectures, delivered 

 at the Brooklyn Academy of Music in 1862, under 

 the title of The Graham Lectures on the Power, 



