Mabch 26, 1909] 



SCIENCE 



517 



plateau around them, this is not the ease. The 

 islands lie on the leeward side of the Gulf Stream, 

 and the rich pelagic life of the great tropical 

 current is constantly drifted upon their shores. 



" Expeditions have for generations brought tons 

 of preserved specimens of tropical forms home to 

 our museums and colleges, where they have been 

 studied and named, but as yet we Ijnow sadly 

 little of the living animals of the tropics, their 

 habits, development and physiology. The labora- 

 tory, therefore, aims chiefly to encourage research 

 in these new fields, and to this end many of our 

 leading investigators and most promising young 

 workers in research have been invited to pursue 

 their studies at Tortugas. 



" The laboratory is now entering upon its fifth 

 year. Two volumes of its researches have been 

 published by the Carnegie Institution, and ten 

 other papers have been published in various sci- 

 entific journals, and the amount of research work 

 now in press greatly exceeds that yet published. 



" The lecturer then reviewed some of the more 

 generally interesting, although not necessarily the 

 most important, researches, as follows: The late 

 Professor William K. Brooks, of Johns Hopkins 

 University, carried out interesting studies of the 

 pelagic Solfw of the Tortugas, his papers being 

 excellently illustrated by the drawings made by 

 Mr. Carl Kellner. Brooks and McGlove find that 

 the lung of the prosobranchiate gasteropod Am- 

 pullaria is developed out of a thickening, or ridge, 

 of the epithelium of the mantle, and arises simul- 

 taneously with the gill and osphradium, all three 

 being homologous organs. There is probably no 

 phylogenetic relationship between the lung of 

 Ampullaria and that of the pulmonates. Ampul- 

 laria is a large brown snail which lives in the 

 fresh water of the Everglades, and lays eggs in 

 pearl-like clusters on the stems of grasses above 

 the water-line. 



" Mr. Frank M. Chapman, of the American Mu- 

 seum of Natural History, describes the nesting 

 habits of the booby {Sula leucogastra) and of the 

 frigate bird {Fregata aquila) upon the isolated 

 rocky island of Cay Verde in the Bahamas. Per- 

 mission to study these birds was generously 

 granted by his excellency. Sir William Grey- 

 Wilson, in his official capacity as governor-in- 

 council of the Bahamas. Specimens for a ' group ' 

 of the frigate birds were collected and these are 

 now beautifully displayed in the American Mu- 

 seum in New York. Mr. Chapman found the 

 nesting season of both boobies and frigate birds 

 to be at its height early in April, the birds having 



apparently come to the island to nest in February. 

 He found that the boobies always lay two eggs, 

 but rear only one young bird. 



" Professor Edwin G. Conklin, of Princeton Uni- 

 versity, studied the structure of the egg of the 

 ' thimble jellyfish,' Linerges mercurius, which ap- 

 pears in vast breeding swarms upon the surface in 

 the spring at Tortugas, and the Bahamas. He 

 discovered that these medusae always spin in an 

 anti-clockwise direction as they progress through 

 the water if viewed from the oral pole. The eggs 

 consist of three easily distinguished substances. 

 A peripheral layer of clear protoplasm which 

 becomes the peripheral layer of the embryo and 

 gives rise to the cilia, an intermediate layer of 

 closely crowded yolk spherules which constitute 

 the principal parts of all of the cells of the gaa- 

 trula and blastula, and an inner mass of dissolved 

 yolk which is poured into the cleavage-cavity and 

 probably serves as a source of nourishment. 



" Dr. E. P. Cowles, of Johns Hopkins, made an 

 elaborate study of the habits of the 'ghost crab,' 

 Ooypoda arenaria, and finds that it probably can 

 not distinguish color as such but detects simply 

 a difl'erence between light and shadow. It can 

 form simple associations and displays memory. 

 It has apparently no sense of hearing, but its 

 otocysts are organs of equilibration. It changes 

 color under the influence of light and temperature, 

 but this change does not occur if the crab's eyes 

 be blackened. 



" Dr. H. E. Jordan, of the University of Virginia, 

 carried out a very elaborate series of studies upon 

 the histological structure of the eggs of echino- 

 derms and of the walking-stick-insect, Aplopus. 

 The germinal spot in echinoderm eggs appears to 

 be in part at least a storehouse of material which 

 is to contribute in the formation of the chromo- 

 somes. He finds in Asterias and Bipponoe that 

 the chromosomes do not arise out of the nucleolus, 

 but the latter contribute nutritive substance to 

 them. In the walking-stick-insect, Aplopus, he 

 finds that half of the spermatozoa have eighteen, 

 and half seventeen chromosomes, and the acces- 

 sory chromosome is large and U-shaped and prob- 

 ably determines the female sex. 



" Dr. Charles E. Stockard, of the Cornell Medical 

 College, and Dr. Charles Zelemy, of Indiana Uni- 

 versity, found, working independently, that in the 

 scyphomedusa Cassiopeia xamoohana removing a 

 greater number of the mouth-arms causes each 

 and every arm to regenerate faster. Stockard 

 finds also that although regeneration of each and 



