DEPARTMENT OF MARINE BIOLOGY * 



Alfred G. Mayer, Director. 



From October 15, 1907, to February 27, 1908, the Director was absent in 

 Europe making a study of Medusae in order to obtain information required in 

 the writing of a work upon the Medusae of the world. During October and 

 November these studies were carried out at Mousehole, on the coast of Corn- 

 wall, England, and during the winter at the Naples Zoological Station, w^here 

 the director, Geheimrath Professor Dr. Anton Dohrn, and his able corps of 

 associates, were untiring in their generous efforts to place all the facilities of 

 this greatest of all marine laboratories at our disposal, and it is with a feeling 

 of enduring gratitude that I now avail myself of the pleasure of expressing 

 my sense of indebtedness to the intelligent kindness of these gentlemen, to 

 whose efforts the success of my studies at Naples is due. 



Sixty-seven species of European Medusae were figured and studied during 

 this visit to Europe; and I was also enabled to consult certain rare publica- 

 tions not found in American libraries. 



The yachts Pliysalia and Sea Horse remained moored in the Miami River, 

 Florida, throughout the w^inter and were thoroughly overhauled, so as to be 

 ready for service early in April. 



Dr. T. Wayland Vaughan, of the U. S. Geological Survey, was then taken 

 upon a cruise the object of which was to study the biological conditions of the 

 coral reefs of the Florida and Bahama region. Landings were made upon 

 many of the Florida coral islands, as the Physalia and the Sea Horse cruised 

 down on the inner side of the keys through the Gulf of Florida from Miami 

 to Key West. Excursions were also made across the Hawk Channel, and be- 

 yond the Gulf Stream to the Bahama side. Dr. Vaughan was untiring in his 

 zeal to avail himself of every opportunity in these studies, and he discovered 

 a number of new and interesting facts concerning the associations of the vari- 

 ous species of corals with reference to situation upon the reefs, depth, strength 

 of currents, prevalence of silt, purity of water, etc., as well as certain impor- 

 tant matters in respect to the origin and structure of the reefs. Upon arrival 

 at Tortugas he proceeded to obtain the planula larvae of certain corals, which 

 are now being reared under observation in natural conditions, thus giving an 

 accurate idea of the normal duration of the free-swimming stage, rate of 

 growth, etc. His research, which is unique in its character, must be carried 

 on for several years before decisive results can be obtained. 



* Laboratory located at Dry Tortugas, Florida. Grant No. 478. $13,000 for investi- 

 gations and maintenance. (For previous reports, sec Year Books Nos. 3, 4, 5, and 6.) 



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