168 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



lerpa, Laurencia, Blodgettia, Liguria, and Sargassnm. Professor Farlow, 

 who examined the algse collected, notes as an interesting acquisition from 

 the Bahamas specimens of Caulerpa Webbiana, thus far known only from 

 the Canaries. 



Dr. T. W. Richards was kind enougn to have some analyses made of 

 bottom specimens selected with regard to their locality on the banks: 

 one specimen off the west shore of Eleuthera from two fathoms of water 

 to represent the bottom on the interior edge of the bank ; one on the 

 middle of Salt Cay Bank, half-way between Elbow Cay and Anguila from 

 three fathoms, and one from Exuma Harbor in two fathoms, to represent 

 the bottom on the outer weather edge of the bank ; one specimen from 

 Bernini, in two fathoms of water, to represent the bottom on the lee 

 side ; and a sample of the white marl ofl' Billy Island, in one and a half 

 fathoms. 



The analyses, made by Mr. Donald Churchill, show a variation of the 

 percentage of CaO between 52.38 and 53.43, with the exception of the 

 sample from the west coast of Eleuthera, in which the percentage is only 

 45.94. This bottom specimen was composed in great part of fragments 

 of Orbitolites, with comparatively little aiolian sand, while the other sam- 

 ples varied from the impalpable powder of which the white marl is com- 

 posed to finer and coarser seolian sand, and to a bottom consisting of 

 fragments of broken shells of NuUi pores, corallines, Millepores, corals, 

 Gorgonians, and coarse seolian sand. 



The percentage of CaO (average of two analyses) in the specimens 

 of bottom from off the west side of Eleuthera, in two fathoms, is 45.95 ; 

 from the outer edge of the bank, Exuma Harbor, in two fathoms, 53.38 ; 

 from the western edge of the bank, North Bemini, in two fathoms, 

 52.46 ; half-way across Salt Cay Bank, in three fathoms, 52.39. 



A qualitative examination of the white marl showed a very large quan- 

 tity of CaCOs, a little magnesic oxide, a little ferric oxide, and a very little 

 silica and organic matter. Five grams of the powdered CaCOg bottom lost 

 7± milligrams upon being washed with 200 c.c. of water. Five grams 

 of the same were digested with 250 c.c. of sea water (from the Bahamas) 

 for a week. Upon washing upon a Gooch crucible with 200 ± c.c. of 

 water, the CaCOg was found to have lost 3± milligrams. The carbonate 

 was tested qualitatively for sulphuric acid, which was found in small quan- 

 tities. A saturated solution of gypsum in water at 20° contains about one 

 gram of CaO per litre. Nearly four times as much dissolves in a saturated 

 salt solution. Dr. Richards hopes to make some additional exj)erimental 

 trials with reference to the solubility of gypsum in sea water. 



