DEPARTMENT OF ^MARINE) BIOLOGY. 121 



The collection made by Prof. Ulric Dahlgren at the Laboratory in 1906 has 

 provided him with certain material the study of which has contributed to the 

 valuable Text-Book of the Principles of Animal Histology, 1908, by Ulric 

 Dahlgren and William A. Kepner. 



Before presenting the preliminary reports of investigators who have studied 

 at the Laboratory during 1908, the following brief summary of the results 

 attained may be of interest : 



Dr. R. P. Cowles studied the righting reaction of several species of brittle- 

 stars. His observations are very extensive, and have been carried out with 

 care to avoid possible errors of interpretation. He prefers at present to re- 

 frain from announcing any conclusions. 



Mr. Davenport Hooker discovered that the newly-hatched young of the 

 loggerhead turtle are strongly attracted toward the color blue. They crawl 

 immediately toward a pane of blue glass thrust upright in the sand, or even to 

 ^ piece of blue paper. They have no preconceived idea of the appearance of 

 the ocean, and will turn away from the sea if it be seen through yellow, red, 

 or green glass. They are attracted toward the ocean solely by the blue color 

 of its waters. Mr. Hooker also finds that the young turtles tend to crawl 

 down-hill, and are attracted by large areas of light of low intensity rather 

 than by small areas of high intensity. 



Prof. Edwin Linton continued his systematic study of the parasites of fishes 

 with even better fortune than formerly. He finds that there are very few 

 flesh-parasites in the Tortugas fishes. Also the Acanthocephala and Nema- 

 toda are more abundant in northern than in tropical fishes. On the other 

 hand, the Cestodes and Trematodes are fully as abundant in Tortugas as in 

 northern fishes. On the whole, the Florida fishes appear to be relatively free 

 from parasites as compared with northern ones. 



Dr. J. F. McCIendon studied the habits and feeding reactions of a new spe- 

 cies of sea-anemone of the genus Cradactis, which walks upon its tentacles. 

 He also found a remarkable Potoniid crustacean which appears to have be- 

 come convergently modified in structure and habits, so as to closely resemble 

 the common Synalpheus, together with which it lives in the cavities of logger- 

 head sponges. 



Dr. Raymond C. Osburn made the first extensive systematic stuay of the 

 Bryozoa of the shallow water of the Florida region. He found about 50 spe- 

 cies, at least 20 of which are new to the North American fauna, or to science. 

 At least 15 species are characteristic of the Mediterranean, and 12 of Aus- 

 tralia and the East Indian region. The fauna of Tortugas is decidedly trop- 

 ical, only 10 species of Bryozoa being found both off the New England coast 

 and at Tortugas. The Bryozoan fauna of Tortugas is much richer than we 

 have hitherto believed it to be. 



