124 REPORTS ON INVESTIGATIONS AND PROJECTS. 



In addition to the above, Messrs. Cowles, Hargitt, Hartmeyer, Harvey, 

 Hooker, Linton, Mast, Mayer, McClendon, Pratt, Stockard, Stromsten, Ten- 

 nent, and Vaughan have contributed articles which will appear in publications 

 132 and 133 of the Carnegie Institution of Washington. 



On behalf of the laboratory it gives me pleasure to express our gratitude 

 to Commodore William H. Beehler, U. S. Navy, commandant of the naval 

 station at Key West, whose kind and constant interest has been displayed 

 toward the laboratory and all connected with it upon every possible occasion, 

 and in default of whose friendship we could not have adequately maintained 

 the station. 



We are also deeply indebted to Dr. E. K. Sprague, director of the Marine 

 Hospital at Key West, whose efficient and kindly care secured the recovery 

 of one of the investigators from a serious illness. 



During the season President Woodward, of the Institution, paid an all too 

 brief visit to the laboratory, and it is the hope of the Director and his asso- 

 ciates that in coming years such visits may be both frequent and more 

 prolonged. 



On July 28, 19 10, the yacht Physalia and her launches were safely laid up 

 in the Miami River, Florida, where they will remain until after the hurricane 

 season. 



The reports of the investigators who studied at the laboratory during the 

 summer of 19 10 are herewith presented. 



PRELIMINARY REPORTS OF RESEARCHES, SEASON OF 1910. 

 Report of Researches upon Actinians, by L. R. Cary, Princeton University. 



REARING OE ZOANTHEEEA AND ZOANTHINA (l.ARV^ OE SEMPER AND OF 



hensen). 



Two species of the former genus and one of the latter were found in abun- 

 dance in the eddies at the borders of the Gulf Stream south of Tortugas. In 

 attempting to rear these forms both the method of changing the water in the 

 aquaria twice daily and that of keeping them in a jar with a culture of 

 diatoms were used. The first-mentioned method was the more successful. 



The Zoanthinae (Hensen's larvae) alone underwent the transformation 

 from the free-swimming larvae to an apparently normal actinian with eight 

 tentacles. When the transformation was to take place the circular band of 

 large cilia was resorbed, the larvae became inactive, and settled to the bot- 

 tom of the jar, becoming attached by the aboral end, the one formerly ante- 

 rior in locomotion. 



After their attachment the appearance of the tentacles took place in the 

 following order: First a single one made its appearance, then one opposite 

 to it (180° away), and then one on each side half-way between the previous 

 pair. This stage with four tentacles lasted for two to three days. 



The next lot of tentacles, four in number, made their appearance simul- 

 taneously, one arising between each two of those already present. None of 



