128 REPORTS OF INVESTIGATIONS AND PROJECTS. 



Hartmeyer, R. Die westindischen Korallenriffe und ihr Tierleben. In Meereskunde, 



Jahrg. 3, Heft 2, Berlin, 40 pp. 1909. 

 Mayer, A. G. On the use of carbon dioxide in killing marine animals. In Biological 

 Bulletin, vol. 16, p. 18. 

 Also: On the use of magnesium in stupefying marine animals. Ibid., vol. 17, p. 



341. 1909. 

 Also : The relation between ciliary and muscular movement. In Proc. Soc. Experi- 

 mental Biol, and Medicine, vol. 7, 1909. 



Messrs. McClendon, Hooker, Hargitt, and Stockard have presented papers 

 for publication in the forthcoming vohime 3 of Papers from the Tortugas 

 Laboratory of the Carnegie Institution of Washington, and other articles are 

 being prepared by Messrs. Cowles, Harvey, Linton, Osbum, Stromsten, Ten- 

 nent, Vaughan, and the Director, and thus material for at least one more 

 volume is assured. 



We now present the preliminary reports of this season's studies : 



PRELIMINARY REPORTS OF RESEARCHES, SEASON OF 1909. 



Preliminary Report on the Behavior of Bchinoderms, by R. P. Cowles, Johns 



Hopkins University. 



During the summer of 1909 the study of the behavior of Echinoderms, 

 begun in 1905, was continued. A special investigation was made of the re- 

 actions of Echinaster crassispina to light, of the factors determining the 

 method of righting, and of locomotion. The following is a brief statement 

 of the results : 



( 1 ) Echinaster in locomotion does not show any tendency to use a special 

 ray, or pair of rays, as directors. 



(2) With fresh material, and with the light excluded, it was found that 

 different individuals of Echinaster which had been inverted did not right 

 themselves on the same pair of rays. It was also found that in long series of 

 trials repeated day after day the pair used the majority of times on one day 

 was often not the same on succeeding days. The experiments did, however, 

 make it clear that an individual sometimes shows a decided tendency to right 

 itself on a certain pair of rays. Fatigue, unhealthy conditions, and injury are 

 important factors. My experiments lead me to believe that the behavior with 

 reference to the rays used in righting is controlled by physiological condi- 

 tions rather than by structural ones. 



(3) The direction of locomotion just before a trial in righting takes place 

 does not seem to influence the selection of the pair of rays used in the 

 righting. 



(4) The tilt of the bottom upon which the starfish is lying, when small, 

 does not affect the selection of the rays in righting; but when the angle is 

 10° or more, there is a tendency for Echinaster to right itself down-hill irre- 

 spective of the rays used. (Light excluded.) 



(5) Ophiuroids and some starfishes which are considered as "negatively 

 phototactic" to daylight right themselves away from the source of light. This 

 one would naturally expect. Echinaster and probably other starfishes which 

 are considered as "positively phototactic" to daylight also right themselves 

 away from and then move toward the source of light. This phenomenon is 



