n-PLANKTONIC STUDIES: A COMPARATIVE INVESTIGATION 

 OF THE IMPORTANCE AND CONSTITUTION OF THE PELAGIC 

 Fx\UNA AND FLORA. 



By Ernst H.eckel. 

 [Translated by George Wilton Field.] 



TRANSLATOR'S PREFACE. 



Prof. Hteckel's " Plankton- Studien" first appeared in the Jenaische 

 ZeitschHft, vol. xxv, first and second parts, 1890. It was immediately 

 published in separate form by Gustav Fischer, of Jena, and attracted 

 much attention on the Continent and in Enfjland. The subject, "a 

 comparative study of the importance and constitution of the marine 

 fauna and flora," is presented in Prof. Ha^ckel's usual pleasing style, 

 and the work can not fail to be of value to all interested in the bio- 

 logical sciences, to the general reader as well as to the specialist. It 

 derives especial interest in connection with the work of the Fish Com- 

 mission, from its broad discussion of tliose many imi)ortant elements 

 which enter into the food supply of all pelagic fishes, such as the 

 mackerel and menhaden, and, considering the extensive physical inves- 

 tigations now being conducted in our coast waters by the schooner 

 Grampus, its publication at the present time will prove exceedingly 

 advantageous. 



The terminology used by Prof. Hreckel may at first seem formidable, 

 but this difficulty is more fancied than real. The terms are formed 

 upon correct analogies, and most of them will probably find a perma- 

 nent place. The definite restriction of the meaning of terms is a funda- 

 mental necessity in every science, and for the lack of this the branch 

 of biology here considered is in a very unsatisfactory condition. The 

 auth(n', first of all, proposes certain terms with a definite meaning. 

 The word "i)lankton," from the Greek TzXa^'xn'x;, wandering^ roamimj, was, 

 1 believe, first em])l()yed by Hensen in place of the German " Auftrieb," 

 to designate all phmts and aninuxls found at the surface of the ocean 

 which are carried about involuntarily in the water. Hasckel adopts this 

 term, but objects somewliat to the meaning at present attached to it. 



Particularly valuable for us is the general review which the author 

 gives of the discovery and growth of our knowledge of this branch, 



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