116 REPORT OF THE COMMISSIONER OF FISHERIES. 



The parasites of fishes. By Edwin Linton, Ph. I>., professor of biology, Washing- 

 ton and Jefferson College. 



Physiology of the lateral-line organs of fishes. By George H. Parker, Ph. D., 

 assistant professor of zoology, Harvard University. 



A synopsis of the annelids of the Woods Hole region. By J. Percy Moore, Ph. D., 

 instructor in zoology, University of Pennsylvania. 



The total number of investigators who availed themselves of the 

 privileges of the laboratory during the summer was 30, the greatest 

 number at any one time being 20. These men represented two gov- 

 ernment departments and 16 educational institutions, ranging from 

 Alabama to Vermont and west to Illinois. The nature of their inves- 

 tigations is indicated below: 



Artificial sea waters as tested in aquaria. — At the suggestion of Mr. W. de C. Ravenel, 

 representative of the Bureau of Fisheries at the St. Louis Exposition, experiments 

 were made under authority of the Secretary of Agriculture and of the Commissioner 

 of Fisheries, to determine, if possible, how far it may be practicable to make 

 artificial sea water capable of sustaining marine plant and animal life. This work 

 was conducted by Dr. Rodney H. True, physiologist of the Department of Agricul- 

 ture, assisted l)y Mr. W. O. Richtman, of the Department of Agriculture, and Mr. 

 Grant Smith, graduate student of Harvard University. 



Experiments were made with artificial sea water prepared in two ways: (1) By 

 dissolving in distilled water the complete salts of the sea, obtained by evaporation; 

 (2) by dissolving in distilled water chemically prepared salts in proportions deter- 

 mined by analysis. The Challenger analyses by Dittmar were used. Aquaria were 

 provided with artificial waters prepared according to each of these methods and with 

 sea water dipped from the current at the end of the wharf at the AVoods Hole station. 

 Two sets of such aquaria were prepared: (1) Standing aquaria kept at constant salt 

 content by the addition of fresh water; (2) aquaria through which a small stream of 

 water was kept flowing, providing thereby a system of closed circulation. 



Aquaria thus prepared were stocked with both plant and animal life, the plants 

 most used being green forms common at Woods Hole — Cladophora, Enteromorpha, 

 Viva, and Aghardiella tenera. Many types of animal life were studied, including 

 especially sea anemones {Metridium), starfish (Asterias), medusee (Gonionemus), 

 squid (Loligo), and fish (silversides, scup, pipe-fish, etc.). The general result may 

 be stated as follows: Sea anemones seemed to flourish in all the media during the 

 period under observation. ' Starfish survived and behaved normally in the water 

 made from evaporated sea salt, but in some cases showed symptoms of injury in the 

 synthetic solution. Gonionemus survived for several weeks in both solutions, but 

 appeared to suffer from its contact with other forms of life in the aquaria. The squid 

 could not be made to survive for more than a few days in any medium, artificial or 

 natural. It died in the synthetic solution in less than ten minutes, with violent 

 symptoms, but survived in the other artificial solution as long as in the natural sea 

 water. Fish, including delicate forms like Menidia, seemed in all cases to live as well 

 in the artificial solutions as in the natural. Several other forms of fish and inverte- 

 brates were tested in various ways, with the general result that the artificial solution 

 made from the salt obtained by evaporation permitted survival to a degree not clearly 

 different from that seen in sea water. The synthetic artificial solution seemed equally 

 favorable to most forms, but distinctly less so to a few. 



The edible lameUlbranchs as a source of infection. — This research was conducted by 

 Dr. George Wilton Field, of the Massachusetts State Board of Health, assisted by Dr. 

 C. A. Fuller, and involved a study of the relations between shellfish and sewage 

 bacteria, with experiments designed to answer the following questions: (1) Are 



