122 REPORTS ON INVESTIGATIONS AND PROJECTS. 



engaged upon the intensive study of the reef corals of Florida, and in order 

 to render his conclusions of wide import, it seemed desirable that he should 

 visit the richest barrier reef of the Atlantic — that lying along the eastern 

 coast of Andros Island from the South Bight to Morgan's Bluff. 



Moreover, the work of G. Harold Drew, esq., of Cambridge University, 

 had demonstrated that off Port Royal, Jamaica, and at Tortugas, Florida, a 

 bacillus which is abundant in the surface-waters of the tropical sea denitrifies 

 the nitrates and nitrites, giving off free nitrogen, probably in the manner 

 observed by Bauer and by Brandt. Drew also found that the activity of this 

 bacillus caused precipitation of calcium carbonate in the warm surface layers 

 of the ocean to a far greater degree than one would have been led to suspect 

 from the researches of Forchhammer, and of Murray and Irvine, who ob- 

 served the precipitation of calcium carbonate with liberation of ammonia. 

 Shells and corals are probably formed in this manner, but these authors 

 appear to have overlooked the importance of the precipitation of calcium 

 carbonate in some such manner by bacterial action, yet Drew discovered that 

 the vast submarine limestone deposits of the Florida-Bahama region, which 

 have hitherto been called "coral muds," are not chiefly composed of shells, 

 corals, echinoderms, or the skeletons of nullipore algae, but of finely-divided 

 particles of limestone which have been precipitated through the agency of 

 marine bacteria. It became important, therefore, for him to extend these 

 studies to the quiet waters of the deep Tongue of the Ocean off Andros 

 Island, where the currents might not be strong enough to cause anything like 

 the ascending and descending masses of cold or warm waters observed in 

 the Gulf Stream region. Thus in this deep and presumably stagnant water 

 he hoped to determine the bathymetrical distribution of this bacillus, and his 

 studies in this respect were altogether successful. 



The Anton Dohm was equipped with a self-closing Nansen-Bigelow net 

 with which the Director hoped to gain an idea of the bathymetrical distribu- 

 tion of the surface, intermediate, and bottom fauna of the deep water of the 

 Tongue of the Ocean, but owing to the prolonged rough weather and the 

 necessity that Mr. Drew's research should take precedence over other mat- 

 ters, but little could be done except to discover that the region is a rich one 

 for deep-sea pteropods, Crustacea, siphonophores, and medusae. A special 

 expedition will be undertaken to attempt the serious study of this region, for 

 one would expect this deep water to be less disturbed by currents and eddies 

 than are most parts of the Florida-Bahama region in the neighborhood of 

 the Gulf Stream. 



Dr. Paul Bartsch accompanied the expedition to assist Dr. Vaughan in 

 collecting corals and also to study the mollusca, in the knowledge of which 

 group he is an expert. He collected many thousands of Cerion of various 

 races or species, each islet of the Andros group seemingly having its own 

 peculiar variety of this common land-snail. In order to test the effect of 

 local conditions, isolation, etc., several thousand living Cerion from Andros 



