226 CARNEGIE INSTITUTION OF WASHINGTON. 



Considerable attention was devoted to continuing the inspection of the 

 bottom in and around the Tortugas for the location of coral heads, reef 

 patches, etc. As there is no limit to the detail in which such an inspection 

 may be made, it can scarcely ever be regarded as complete, but as all the 

 shoals of the area have been examined in more or less detail, the local distri- 

 bution of corals has been ascertained with moderate thoroughness. 



Dredge hauls were made in Southwest Channel, east of Pulaski buoy, 

 north of the outer end of Northeast Channel, off Loggerhead buoy, in South- 

 west Channel, and at several places in the northern })art of Tortugas lagoon. 

 The material obtained in the five successful hauls, when supplemented by 

 that pre\aously procured by Dr. Maj^er and Mr. John B. Henderson at three 

 other stations, gives a good representation of the corals occurring between 8 

 and 16 fathoms. No corals were obtained in 20 fathoms, probably because 

 of the soft mud bottom. Bottom samples were taken while dredging. As 

 the species of corals were not listed as they came aboard the yacht, a table 

 of the names of the species \vith the depths can not now be presented, but it 

 may be stated that specimens of about 15 species were procured at depths 

 greater than 8 and less than 20 fathoms. 



Successful dredge hauls were also made on the 6^ to 10 fathom shoal, which 

 lies about 7 miles west of Loggerhead Key. This is a rocky shoal, largely 

 covered by dead coral, mollusk shells, and other calcareous debris. 



Measurements and records of the groAvth of corals artificially planted or 

 living naturally attached at Tortugas were repeated. All the living planted 

 corals except those which had settled in planula cultures or had attached 

 themselves at a known time were taken up and shipped to Washington, as 

 were also some of the colonies naturally attached. Except one tile, all colonies 

 resulting from culture experiments were replanted, in the hope of measuring 

 them a year hence. These colonies are from planulae that settled in 1910 

 and in 1915 will be 5 j^ears old. Except the remeasurement of these colonies, 

 the study of groA\i;h-rate is now discontinued. 



One attempt made at Tortugas failed. It is very desirable to ascertain 

 accurately the duration of the free-swimming larval stage of Acropora, but 

 none of the specimens brought into the Laboratory were extruding planulae. 

 The object in procuring this information is to explain the absence of the genus 

 in the Bermudan fauna and its apparent absence in the Hawaiian Islands. 

 I ventured the suggestion in my monograph, "Recent Madreporaria of the 

 Hawaiian Islands and Laysan," that it is perhaps due to the free-swimming 

 stage being of short duration. 



The season of work just ended terminates the field studies I purpose making 

 on the Florida and Bahaman shoal-water corals, by practically completing 

 the program I had laid out when I accepted Dr. Mayer's invitation in 1907 

 to undertake such an investigation, except that I hope in 1915 to remeasure 

 the colonies reared from planulse and if occasion presents itself I will inspect 

 parts of the Florida reef which bad weather has previously prevented my 

 seeing. Before I can write the accoimt of the Florida reef corals and their 

 ecologic relations in the way I have contemplated, the additional data on the 

 temperature gradient of the water with increasing depth and the range of 

 variation in salinity along the reef tract should be available. Additional 

 collections of corals south of Fowey Rock are needed and a collection from the 

 island of St. Thomas is essential to settle some disputed points in taxonomy, 

 as several of the types of Duchassaing and Michelotti came from there. 

 However, some of the data for the final report are already assembled and 

 tabulated, and other data may be put into proper form for publication while 

 awaiting the receipt of additional information and the acquisition of additional 

 collections. 



