372 Coe — A Century of Zoology in America. 



most important contribution to the classification of the 

 respective groups. The relationships of the species, 

 genera and families were recognized with such remark- 

 able judgment that Dana's admirable system of classifi- 

 cation has remained the basis for all subsequent work. 



Dana's critical reviews (25, 202, 321, 1858) of Agassiz's 

 "Contribution to the Natural History of the United 

 States" are among the most interesting of his philosoph- 

 ical discussions concerning the relationships of animals 

 as revealed by their structure, their embryology, and 

 their geological history. 



The remaining zoological articles in this series cover 

 nearly the whole range of systematic zoology. Espe- 

 cially important are the articles by Verrill on coelenter- 

 ates, echinoderms, worms and other invertebrates. 



In the years following the publication of Darwin's 

 Origin of Species in 1859 occur many articles on the 

 theory of natural selection. Some of the writers attack 

 the theory, while others give it more or less enthusiastic 

 support. 



Experimental methods in solving biological problems 

 were little used at this time, although a few articles of 

 this nature appear in the Journal. Of these, a paper by 

 W. C. Minor (35, 35, 1863) on natural and artificial 

 fission in some annelids has considerable interest to-day. 



Of the important zoological expeditions the following 

 may be selected as showing their influence on American 

 Zoology : 



The North Pacific Expedition, with William Stimpson 

 as zoologist, returned in 1856 with much new information 

 concerning the marine life of the coasts of Alaska and 

 Japan and many new species of invertebrates. 



In 1867-1869 the United States Coast Survey extended 

 its explorations to include the deep-sea marine life off 

 the southeastern coasts and Gulf of Mexico under the 

 leadership of Pourtales and Agassiz. 



The Challenger explorations (1872-1876) added greatly 

 to the knowledge of marine life off the American coast 

 as well as in other parts of the world. 



The explorations of the United States Fish Commis- 

 sion succeeded those of the Coast Survey in the collection 

 of marine life off our coasts and in our fresh waters. 

 These have continued since 1872 and have yielded most 



