190 CARNEGIE INSTITUTION OF WASHINGTON. 



and colonial tunicates, the growth-rate is comparable with that in the 

 colder waters. In this connection we might mention the fact that 

 the growth-rate of coral in Samoa is nearly twice as rapid as that of 

 corresponding genera, as determined b}^ Vaughan, in the Florida- 

 Bahama region. 



Professor C. B. Lipman commenced a study of the bacteria of the 

 sea-water of Samoa in an attempt to explain the fact that in the tropi- 

 cal Atlantic we find wide areas of precipitated calcium carbonate, while 

 these are deficient in the Pacific. The precipitation of CaCOs in the 

 Florida-Bahama region has been attributed to the denitrifying in- 

 fluence of the bacillus Pseudomonas colds discovered by G. Harold 

 Drew; but, as a result of later studies by McClendon at Tortugas, 

 there seems reason to suspect that other causes may contribute to this 

 precipitation to an even greater degree than does Drew's bacillus. 



There is m.uch pelagic plant-life, such as Sargassum, Trichodesmium, 

 etc., in the tropical Atlantic, but this is deficient in the warmer parts of 

 the tropical Pacific, and the deficiency of precipitation of calcium 

 carbonate in the Pacific may be correlated with the deficiency of 

 floating plants. Professor Lipman isolated a number of bacteria in 

 the Samoan waters, among them Drew's P. colds, which, when grown 

 in natural sea-water, precipitates a shght amount of calcium carbonate 

 but does not denitrify the sea-water in the process. It will be neces- 

 sary for Professor Lipman to perform corresponding experiments in 

 the tropical Atlantic before final conclusions can be drawn. 



Professor William A. Setchell made a collection of the marine algae 

 and incrusting plants of the reefs of Samoa, in order to determine 

 theu' relation to reef formation. In addition, he collected the terres- 

 trial plants of Tutuila and obtained their native names, an account of 

 the uses made of them by the Samoans, and the tradition of their 

 place of origin. 



Professor A. L. Treadwell, having completed a notable study of 

 the Eunicidse of the Florida-Bermuda West Indian region, accompanied 

 us to Samoa and Fiji in order to extend these studies to the forms 

 found in the Pacific reefs. While en route to the tropical Pacific he was 

 enabled, through the kindness of Professor T. C. Frye, to spend several 

 weeks at the Friday Harbor Marine Laboratory of the University of 

 Washington in Puget Sound, thus broadening the scope of his studies. 



Professor William H. Longley remained two months in Samoa, 

 making a study of the fishes of the reefs, in order to determine the 

 underlying laws in obedience to which then- colors and patterns may 

 have been evolved. He is thus continuing in the Pacific the elaborate 

 studies he has for some years pursued at Tortugas and in the West 

 Indies. By using a diving-hood and observing fishes in theii- natural 

 surroundings he has gathered a great mass of valuable data, and con- 

 cludes that natural selection is the chief underlying factor which has 

 determined the coloration of these fishes. 



