196 CARNEGIE INSTITUTION OF WASHINGTON. 



Floritla-growii specimens was made on the Second Ragged Key north of Sands 

 Key, on Sands Key, Bahia Honda, and three on Loggerhead Key, Tortugas. 



Adult specimens of the first generation were found on the Second Ragged 

 Key north of Sands Key, on Bahia Honda Key, on Boca Grande Key, and on 

 Loggerhead Key. Th(>se a(kilt specimens of the first generation of both races 

 of Florida-grown individuals now enable us to say that a decided change has 

 taken place^that the first generation is not like the parent generation, and 

 that the departures, in some instances, are so pronounced that the specimens 

 would easily be considered distinct species and probably deemed not very 

 closely related to the parent stock by workers in this group, unfamiliar with 

 the history of the material. Moreover, the range of variation in the offspring 

 is wider than that of their parents. 



A complete report upon the work so far done, and the results obtained in 

 these experiments, will shortly be published. 



Report on Investigations at Tortugas, by L. R. Gary. 



STUDIES ON ALCYONARIA. 

 Growth Rate. 



The records of the gro\\i;h rate of several species of gorgonians have been 

 continued, both by means of measurement and photographic records of speci- 

 mens cemented on tiles, as well as by the annual measurement of individuals 

 growing in their natural positions on the reefs. These records now extend 

 over a period of five years, for some species, and cover the growing period from 

 the attachment of the planulse to the attainment of the full size of the colony. 



In one instance it has been possible to observe the reestablishment of the 

 gorgonian fauna over a considerable reef area on the southern end of White 

 Shoal. This portion of the reef was brought above low-water mark during 

 the hurricane of October 1910, so that in January 1911 an area of 2 acres or 

 more was exposed. By June 1911 the easily moved material had been washed 

 from the summit of the reef, so that it was permanently below low-tide mark. 

 This washing of the lighter unattached material continued, so that by the 

 summer of 1912 the surface of the reef had reached its final level. At this 

 time no gorgonians were found at an^^ place on the reef that had been subjected 

 to the heaping up and subsequent removal of the light material by wave 

 action. In September 1913 many small specimens of Gorgonia acerosa were 

 noticed on the reef, but no accurate record of their numbers was made. When 

 counts were made in July of this year an average of 3.7 individuals was found 

 for each square yard as determined from 75 counts. Nearly all of the speci- 

 mens were 2 years old and at least 95 per cent of all those growing on the 

 new part of the reef were of the single species G. acerosa. Farther to the north, 

 on the deeper part of the same reef, several other species of gorgonians are 

 more common than the above-mentioned form, but for some reason the planulas 

 of G. acerosa only had secured attachment in positions favorable for continued 

 growth. 



The i^lanuliE of Briareum sp. were set free in great numbers from colonies 

 brought into the laboratory, and readily underwent their attachment and 

 transformation to form the polyp-bearing colony. 



As complete a collection as possible was made of the alcyonaria from the 

 region about Tortugas on both the shallow and deeper reefs. All the forms 

 secured were photographed and notes were made of their characteristics while 

 living. The results of this work, when combined with those of similar studies 

 at other points in the Florida-Antillean region, will be incorporated in a syste- 

 matic account of the alcyonaria of the section. 



