180 CARNEGIE INSTITUTION OF WASHINGTON. 



normal atmospheric pressure and temperature. This leads one to 

 suspect, but not to conclude, that uncombined carbon dioxide may be 

 present in the surface-water of the sea and that the Tortugas water may 

 thus be capable of dissolving limestone. This matter should, however, 

 be tested by further experiments before we may venture upon any 

 definite statement, and such tests are now being conducted by Drs. 

 Vaughan, Dole, and Tashiro and by the Director. 



Professor Ulric Dahlgren spent nearly six weeks at Beaufort, North 

 Carolina, and succeeded in obtaining the young of the ''star gazer," 

 Astroscopus, in order to study the development and histology of its 

 electric organs, which are formed from modified eye muscles. He has 

 shown that the development of electric tissue in seven types of fishes 

 is independent one of the other and is comparatively recent. For 

 details one should consult not only his report upon the habits of Astro- 

 scopus published herewith, but his interesting paper upon "The elec- 

 tric tissues of Gymnarchus," in Publication No. 183 of the Carnegie 

 Institution of Washington. It is hoped that his interesting studies 

 may be continued in South America and in Egypt. 



Dr. A. G. Mayer made an extensive series of kymograph records of 

 the rate of nerve conduction in Cassiopea at Tortugas. Experiments 

 were carried out upon 211 medusae in diluted and in evaporated (con- 

 centrated) sea- water; also in sea-waters wherein the osmotic pressure 

 was higher than the normal, while the concentration of the electrolytes 

 was that of natural sea-water. It is well known, from the work of 

 Loeb and of Goldfarb, that concentrated sea-water inhibits growth and 

 regeneration to a greater degree than does a corresponding dilution, 

 but the cause of this difference is not known and it is hoped that these 

 kymographic records may throw light upon this matter and enable us 

 to determine the formula expressing the relation between rate of nerve 

 conduction and degree of concentration of the ions surrounding the 

 nerves. Several months must elapse, however, before the thousand or 

 more observations can be tabulated and reduced to mathematical 

 expression. 



Volumes 5 and 6 of Papers from the Tortugas Laboratory (Nos. 182 

 and 183 of publications of the Carnegie Institution of Washington), 

 containing 23 articles, appeared during the year, and the following six 

 papers were also published as a result of studies carried out under the 

 auspices of the Department of Marine Biology: 



Changes in concentration of sea-water and their influence upon regeneration. A. J. Gold- 

 farb, Proc. Society Experimental Biology and Medicine, vol. 10, No. 3, 1913. 



The influence of the central nervous system in regeneration of an annelid worm. Ibid. 



Cell permeabihty for acids. E. Newton Harvey, Science, vol. 39, p. 947, 1914. 



An expedition to the coral reefs of Torres Straits. A. G. Mayer, Popular Science Monthly, 

 vol. 85, pp. 209-231, September 1914. 



Sketch of the geologic history of the Florida reef tract and comparisons with other coral-reef 

 areas. Thomas Wayland Vaughan, Journal Washington Academy Sciences, vol. 4, 

 pp. 26-34. 



The platforms of barrier coral reefs. Thomas Wayland Vaughan, Bulletin American 

 Geographical Society, vol. 46, pp. 426-429. 



