Biologisches Centralblatt, 



Unter Mitwirkung von 



Dr. M. Beess und Dr. E. Selenka 



Prof, in Erlangen Prof, in Miinchen 



herausgegeben von 



Dr. J. Rosentlial 



Prof, der Physiologie in Erlangen. 



24 Nummern von je 2 4 Bogen bilden einen Band. Preis des Bandes 20 Mark. 

 Zu beziehen durch alle Buchhandlungen und Postanstalten. 



XVIII. Band. 15. Jnii 1898. Nr. 14. 



I n h a It : Peck and Harrington, Observations on the Plankton of Puget Sound. - - ZilUiner, 



Ueber tierisches Potamoplankton. Schroder, PlanktologischeMitteilungen. 

 France, Der Organismus der Craspedomonaden. Garbowski, Apathy's 

 Lehre von den leitenden Nervenelementen (IT. Stiick und Schluss). 



Observations on the Plankton of Puget Sound. 

 By J. I. Peck and N. R. Harrington. 



In consequence of former studies in planktonic work in the shallow 

 waters of Buzzards Bay, on the Southern coast of Massachusetts 1 ), 

 the authors of this paper have sought opportunity of studying some 

 of the facts of the vertical distribution of similar forms over greater 

 depths. Such an opportunity came during the Summer of 1896, through 

 the Columbia University Zoological Expedition of that year 2 ) in Puget 

 Sound, on the northwestern, Pacific Coast, of the United States, where 

 our collections were made by the junior author with a simple appa- 

 ratus designed in advance by us both but constructed and operated 

 by him. 



The most recent interpretation 3 ) of the very irregular coast line 

 of the Puget Sound district is that the Cretaceous areas of Oregon 

 have been here turned on edge, while numerous depressions and 

 emergencies of Eocene times augmented by glacial action have 

 resulted in the very deep bays with their many islands, and the deep 

 inland fresh-water lakes of the State of Washington. Other authorities 

 attribute more of these conditions to the action of glaciers alone. In 

 many instances precipitous cliffs dip perpendicularly into the sound 

 for a depth of from 600 to 900 feet, and in water of 30 fathoms 

 average depth there may be a sudden drop over a very limited area 

 to 150 or 200 fathoms. 



1) Sources of Marine Food, U. S. Fish Com. Bulletin, 1895, p. 356. 



2) Described in Trans. N. Y. Acad. Sci., Vol. XVI, p. 33-42. 



3) See American Geologist for March and April, 1897. 

 XVIII. 33 



