166 CARNEGIE INSTITUTION OF WASHINGTON. 



Many of the investigators this season at Tortugas worked upon 

 researches which are to be pubUshed in the forthcoming volumes 5 

 and 6 of ''Researches from the Department of Marine Biology," now 

 in press. Owing to the necessity for shortening the season due to 

 the Australian expedition, only persons who had in previous years 

 studied at Tortugas came again this year to complete or to continue 

 their investigations, the time being too short to permit of any satis- 

 factory progress upon new researches. 



Dr. Paul Bartsch revisited the Florida Keys and Tortugas, upon 

 which, during May and June 1912, he had placed two forms of Cerion 

 taken from the region of Golding Cay, Andros Island, Bahamas.* 

 Young produced by these snails were found upon Ragged Keys, 

 Bahia Honda, and the Tortugas, but in each case they resembled 

 their parents in all respects and had as yet been unaffected by their 

 changed environment. Dr. Bartsch has segregated these young 

 upon Loggerhead Key, Tortugas, and will endeavor to determine 

 whether the next generation still remains true to the ancestral type. 

 Practically every islet of the Great Andros Archipelago has its own 

 peculiar form of Cerion, and Dr. Bartsch's experiments are directed 

 to determine the cause of this remarkable variabilit3^ 



Dr. Gary will spend September and part of October at Tortugas 

 in studying the embrj^ology of Palythoa, the life histories of Hensen's 

 and Semper's larvae, and the growth-rate of Gorgonians. 



Mr. R. B. Dole made determinations of the salinity and other 

 chemical and physical factors of samples of sea-water which had been 

 collected in the Tortugas lagoon and at other places by Dr. Vaughan. 

 He found that the average salinity of Tortugas sea-water is about 

 36.15%o and it is saturated to about 92%o of its capacity with oxygen, 

 but contains no free CO2, the carbon dioxide being either fully com- 

 bined or half combined. There is no detectable difference in the 

 water in the middle of the lagoon at high tide as compared with 

 the water at low tide, yet the salinity of the water in the lagoon 

 remains constantlj^ slightly higher than that of the general ocean 

 surrounding it. 



Dr. Goldfarb succeeded in fusing fertilized eggs of Toxopneustes 

 and Hippono'e, producing in each species twin or multiple larvae; his 

 results will appear in one of the forthcoming volumes of Researches 

 from the Department of Marine Biology. 



Professor Gudger completed his anatomical studies of the eagle 

 ray and made careful dissections of several species of sharks and 

 teleosts, as described in his report. 



Mr. K. S. Lashley served as assistant to Professor Watson, and 

 himself carried out a research upon the sense of locality displayed by 

 the gulls of Bird Key. 



*Figures of these two forms will be found in Smithsonian Miscellaneous CoUectioDS, 

 vol. 60, p. 60, 1913. 



