124 REPORTS O? INVESTIGATIONS AND PROJECTS. 



Report on the Instincts and Habits of Newlv-hatchcd Loggerhead Turtles, 

 by Davenport Hooker, Yale University. 



During the summer of 1907 I made some observations on the habits and 

 early instincts of the loggerhead turtle, at the Tortugas Laboratory. This 

 past summer (1908) I repeated these experiments and extended them. As a 

 result of this more thorough investigation, I am led to believe that the de- 

 ductions I drew last year were partially erroneous, due to lack of sufficient 

 analysis of the environmental factors. At the present time I feel justified in 

 making the following statements as borne out by the facts observed : 



(i) The newly-hatched loggerhead turtle moves away from transparent 

 and opaque red, orange, and green, and from green bay-cedar bushes, and 

 moves toward transparent or opaque blue. The colors used were found to be 

 impure, so that their exact value is unknown, but it would seem that an ex- 

 cess of a color produces the effect. This, with a positive reaction to a down- 

 ward incline, enables the young turtle to reach the sea. This reaction to color 

 probably involves the matter of difference in intensity, but to what extent I 

 am unable to state. 



(2) After entering the water, the animal swims out to sea, apparently 

 attracted by the darker blue of the deeper water. The position of the sun is 

 an entirely negligible quantity. 



(3) When on the beach in a large sand-pit with level floor, from which 

 pit sight of the bushes and the ocean is excluded, but from which the sun is 

 plainly visible, there is exhibited no tendency to move in any definite direction. 



(4) Under a restricted environment, the young turtle is, in addition to its 

 chromotropic response, positively phototropic and responds to a large surface 

 of light of comparatively low intensity rather than to an illuminated point of 

 high intensity, as was found by Dr. Leon J. Cole to be true in the case of 

 many positively phototropic animals having image-forming eyes. 



(5) The reactions of the young turtle are not modified by sound or odor 

 of the sea, nor by a tank of sea-water where there is not sufficient quantity to 

 give color. 



Preliminary Report on Helminths, by Bdzvin Linton, JVashington and 



Jefferson College. 



Following is a preliminary report on helminths collected at Tortugas in the 

 season of 1908, to which is added a note on the trematodes collected the two 

 preceding seasons : 



Source of material. — The fish which were examined for parasites were, for 

 the most part, taken in traps among the coral-heads and in the shallow water 

 on the north shore of Loggerhead Key. A large nurse shark (Ginglymos- 

 tomum cirratum), 2 specimens of spotted stingray {^tiobatis narinari), and 

 3 species of trunk-fish (Lactophrys) were speared by Capt. L C. Lundblom 

 on the reef near Garden Key. Two tiger-sharks (Galeocerdo tigrimis) were 

 taken before I reached the Laboratory. The cestodes which were found in 

 them were preserved in formalin. Again I am obliged to identify this host 

 by means of its parasites (see Year Book of the Carnegie Institution for 

 1906, pp. 113 and 116; the same, for 1907, p. 114). A stingray which I have 

 recorded under the name Dasyatis sayi was also collected before my arrival 

 at the laboratory and was thought to be Dasyatis hastatus. It was a female 

 with 2 young. The latter were saved. They appear to belong to the former 



