DEPARTMENT OF MARINE BIOLOGY. 123 



Island were taken to Florida and colonies were planted on the Ragged Keys, 

 Indian Key, The Tea-Table, Newfound Harbor Keys, Duck Key, Bahia 

 Honda, Boca Grande, and Tortugas, Florida. The results of these experi- 

 ments will be awaited with interest, for so plastic an organism as Cerion may 

 be expected to vary appreciably in a few generations when subjected to such 

 widely changing environmental conditions, and light may thus be thrown 

 upon the nature of the causes that produce the extraordinary variability in 

 other mollusca such as the Partulae and Achitinellidce of the Pacific. 



An important discovery made upon the expedition was that of Dr. T. 

 Wayland Vaughan, who agrees with Shattuck and Miller in that the Bahamas 

 for a few feet above tide-level are composed of limestones of submarine 

 origin which have been elevated to form a base upon which the superimposed 

 aeolian limestones have been formed. Vaughan, however, made the addi- 

 tional discovery that this elevated limestone of submarine origin is identical 

 with the Miami oolite of Florida. But the intensive examination of the lime- 

 stones of the Bahamas and of the Florida Keys which we visited in return- 

 ing led him to an even more interesting conclusion. Drew's bacillus, as we 

 have just stated, causes a constant precipitation of calcium carbonate in the 

 warm surface layers of the tropical ocean. This flocculent matter settles, 

 loosely upon the bottom, and, as Vaughan observed, the mud thus formed 

 soon becomes filled with minute bubbles of gases due to the decomposition 

 of the animal and vegetable matter contained within it. These bubbles form 

 either separately or around solid particles. As soon as the bubbles are 

 formed, finely divided particles of limestone are attracted and settle upon 

 their surface films. It is possible that some of the Florida-Bahama oolite is 

 formed in some such manner, but Dr. Vaughan has observed that if finely 

 divided limestone mud be maintained under water in bottles oolites may 

 form independently of bubbles. 



This work of Vaughan upon the oolite was rendered possible through the 

 generous gift by the Hon. John B. Henderson, Regent of the Smithsonian 

 Institution, of an excellent dory launch, which we have seen fit to name the 

 Henderson. This launch is 23 feet long and has a 6-horsepower engine 

 capable of driving her at the rate of 9 miles per hour. The draft is so light 

 that we were able to travel for miles over the shallow flats of Florida in 

 places inaccessible to our other boats. 



One object in seeking Golding Cay Harbor, Andros Island, as our base was 

 that the Great South Bight, which opens to the eastward at this place, per- 

 mitted us to pass through the island in our launch Velella and to study the 

 remarkable "white marl" of its western coast. 



While at Golding Cay, Dr. Vaughan made a collection of the more inter- 

 esting reef corals, and he also measured 135 specimens and cemented them 

 upon tiles, and then affixed them to iron stakes which were driven into the 

 reef in favorable places for observing the growth-rate; for we expect to 

 return to Golding Cay in 1914. 



