220 CARNEGIE INSTITUTION OF WASHINGTON. 



gation with the biometer, this being a more delicate method, as it enables us 

 to detect a quantity of CO2 as small as 0.0000001 gram. The following is a 

 merely preliminary report upon the results thus far obtained, the final con- 

 clusion being reserved for a later report. 



1. Enormous quantities of CO2 can be obtained from the cold sea-water 

 \\'ithout any mechanical disturbance. The quantity of CO2 obtainable from 

 sea-water under this condition is more than 50 times that contained in the 

 same volume of natural air, which may be assumed to contain 3 parts of CO2 

 in 10,000 by volume. 



2. Since many bicarbonate solutions give CO2 with equal ease under similar 

 conditions, one can not say Avhether the CO2 obtained from the sea-water is 

 entirely due to decomposition of a bicarbonate or to the setting free of gas 

 which existed as CO2 in the sea-water itself, for the amount of CO2 given off 

 by the sea-water is so large that it is impossible to take an amount of sea- 

 water small enough to contain the minimum amount of detectable CO2, 

 namely, 0.0000001 gram. On this account, the total CO2 obtainable from 

 a known amount of sea-water could not be determined. 



3. In an attempt to settle this problem, the following lines of investigation 

 are now in progress: 



(a) One must devise an apparatus which mil enable one to dilute CO2 

 obtained from a small amount of sea-water. 



(6) By calculating the maximum amounts of CO2 obtainable by the same 

 concentration of the carbonate and bicarbonate as that of the sea-water. 



(c) By determining total carbonate in sea-water before and after aeration 

 and the amount of CO2 driven off by aeration, the method I have been using 

 for determining CO2 production in sea- water. It is obvious that if the total 

 carbonate as CO2 before aeration is equal to that of CO2 driven off by aeration 

 plus the total carbonate as CO2 present in the sea-water after aeration, we 

 may calculate how much CO2 is due to the decomposition of bicarbonate. 

 The fact that the sea-water gives off free CO2 by aeration suggests from an 

 equilibrium point of view that there must be some free CO2 present in the 

 sea-water, although it may be small in amount. 



4. Sea- water seems to lose CO2 on standing in contact with pure natural air 

 containing the normal amount of CO2, provided no bacterial decomposition 

 takes place. 



5. Judging from the preliminary experiments cited above, there is a possi- 

 bility of free CO2 being present in sea-water, but the evidence is not yet 

 conclusive. 



Researches upon Annelids at Tortugas, by A. L. Treadwell. 



My work at the Tortugas Laboratory in the season of 1914 was a continua- 

 tion of a systematic study begun in 1910, on the polychaetous annelids of the 

 family Leodicidae (Eunicidse). In this work I was again able to secure the 

 efficient assistance of Mr. S. C. Ball as artist. We now have water-color 

 paintings of the living animals of 20 species belonging to this family, with 

 drawings of anatomical details amounting in all to 210 figures. It is my 

 intention to continue this work to include a study of all members of the family 

 which occur in West Indian waters. 



Owing to the absence of mud flats, burrowing annelids do not occur in the 

 Tortugas region, the only exceptions being a few forms, as sabellids and a 

 few arenicolids, burrowing in the mud at the l)ottom of the moat at Fort 

 Jefferson. The great majority live either in crevices in the coral rock or in 

 tubes attached to the under side of stones, shells, or (at Fort Jefferson) 

 attached to bricks of the moat wall. Wherever a coral rock has been per- 

 forated by boring sponges and moUusks, or wherever a crevice has been formed 



