DEPARTMENT OF MARINE BIOLOGY. 177 



interesting stage, but it is hoped that it may soon be continued under 

 better conditions. 



During the summer of 1914, Professor Henry H. Donaldson placed 

 upon East Key, Tortugas, 8 white rats, an albino of the Norway rat. 

 These apparently increased and seemed to be numerous in the summer 

 of 1915, but upon his visiting East Key in 1916, they were nearly 

 extinct, for only two females could be captured in traps. Accordingly, 

 in July 1916, Professor Donaldson brought from the Wistar Institute 

 Laboratory, in Philadelphia, about 100 white rats, 60 of which he 

 introduced upon East Key and 24 upon Garden Key. He intends to 

 revisit the Tortugas in 1917 and to determine the effects of isolation, 

 climate, and restricted food upon the brain-weight and general 

 anatomy of these animals. He found that the food of the rats upon 

 East Key, which is a small sandy islet covered with low bushes, con- 

 sists of grass-seed and shore crabs (Ocypoda). They lack fresh 

 water, excepting that derived from the occasional rains of this arid 

 region and from dew. Thus their struggle for existence is uncom- 

 monly severe and their margin of safety must be reduced to a minimum. 

 Professor Donaldson's report should be consulted by those interested 

 in the effects of a tropical climate, combined with meager variety in 

 food, upon rats accustomed previously to a wide variety of food in a 

 temperate region. 



Dr. Skinkishi Hatai assisted Professor Donaldson in the study of 

 the white rats and also carried out an elaborate study of the decline 

 in weight and the nature of the substances consumed in starving 

 Cassiopea, the decline of various organs and parts of the body being 

 determined. These studies, it is hoped, he will continue in 1917 at 

 Tortugas. His preliminary report should be consulted by those inter- 

 ested in this subject. He found that there is a remarkable process 

 of adjustment during starvation by virtue of which the proportional 

 weights of the mouth-arms, disk, and velar margin become those of a 

 normal Cassiopea of the size of the reduced animal. His results, 

 although as yet incomplete, show an alteration of nitrogen content 

 as starvation proceeds, thus resembling the condition observed in 

 vertebrates. The loss of weight is practically controlled by the large 

 relative amount of gelatinous substance. 



Professor Edward L. Mark, of Harvard, director of the Bermuda 

 Marine Biological Laboratorj^, was so kind as to extend to Professor 

 A. L. Treadwell an invitation to make use of the facilities of the 

 Bennuda laboratory in the study of the Eunicidse. This research has 

 been pursued by Professor Treadwell for many years, and he has 

 accumulated a valuable collection of drawings. These studies have 

 been conducted at Tortugas and Porto Rico, and it was therefore desir- 

 able that Professor Treadwell should visit Bermuda in order to deter- 

 mine the relationships between the polychaete fauna of the northern 

 and mid-region of the range of this tropical family of worms. Accord- 



