DEPARTMENT OF MARINE BI0E0GY. 121 



Among the more important results of the season's work, Dr. L. R. Cary 

 succeeded in rearing Hensen's larva of Zoanthinse until it passed into the 

 edwardsia stage with 8 tentacles. He also began a series of growth records 

 and regeneration experiments upon Alcyonaria and carried on a study of 

 artificial parthenogenesis in Palythoa, and of the early stages of development 

 of Fissurella to the free-swimming veliger stage. 



Mr. E. Newton Harvey finds that dilute solutions of chloroform which are 

 too weak to produce cytolysis will increase the permeability of eggs to NaOH. 

 After being fertilized the egg is more permeable to NaOH than it was before 

 fertilization, and this despite the fact that after fertilization it is surrounded 

 by a fertilization-membrane. Mr. Harvey also studied the phenomena of 

 cytolysis in eggs and comes to conclusions which accord with those of Ham- 

 burger and of Koeppe. 



Professor Dr. E. Jorgensen, of Bergen, Norway, studied the Peridiniea of 

 the Tortugas. 



Prof. S. O. Mast found that the eyes of Turbellaria serve to direct these 

 animals in their reactions to light. Without their eyes they do not orient 

 themselves in respect to the direction of a source of light, although they 

 remain sensitive to light, for they become more active when the intensity of 

 light is suddenly increased. Their rate of locomotion is dependent upon the 

 amount of light energy received, not upon a mere change in intensity. Newly 

 regenerated tissue is more sensitive to light than old tissue. The animals 

 can distinguish between the stimulus due to a decrease of intensity and that 

 due to an increase in intensity of light. 



Dr. J. F. McClendon discovered that echinoderm eggs become more per- 

 meable to electrolytes after fertilization or parthenogenesis than they were 

 before the commencement of maturation. The electric conductivity of eggs 

 increases after they have been fertilized or stimulated by acid to develop. 

 It is suggested that development is caused by increase in permeability to 

 anions, allowing the OH ions of the sea-water to enter the egg and accelerate 

 oxidation. McClendon also found that the freezing-point of the sea-water 

 at Tortugas is — 2.06 F. and at Boca Grande Channel — 2.1 1° F. Thus the 

 Tortugas water is practically isotonic with 0.6 molecular NaCl, 0.62 molecu- 

 lar KC1, molecular MgS0 4 or cane sugar, and less than 0.5 molecular CaCl 2 

 or MgCl 2 . The lowering of the freezing-point of Tortugas water as com- 

 pared with that of other laboratories is as follows: Roscoff, — 2.12 ; Tortu- 

 gas, — 2.06 ; Pacific Grove, — 1.90 ; Woods Hole, — 1.82 to — 1.85 . 



In this connection it is interesting to present the results of an analysis of 

 Tortugas sea-water made under the direction of Prof. Frank W. Clarke, of 

 the U. S. Geological Survey. His report follows : 



