BIOLOGY, marine; — MAYER. Ill 



Prof. Ulric Dahlgreii presents the following report of his studies : 



Report of Work Accomplished by Ulric Dahlgren in the Laboratory of the 



Carnegie Institution at the Dry Tortiigas, Florida, during the Summer 



of 1906. 



On June 20 of this year I arrived at Key West. My object in visiting the laboratory 

 was to procure material from Pterophrync histrio and other pediculate fishes to con- 

 tinue my studies of the giant ganglion cell apparatus found in this and other fishes. 

 Also I wished to secure living specimens of Astroscopus to study the electric organs 

 with the Golgi method and the intra-vitam method with methylene blue. 



On the second day we proceeded to the Tortugas and were soon collecting on the 

 reef. I found an abundance of Pterophryne, and secured a splendid series of these 

 fishes prepared in all ways necessary for my work. 



Of Astroscopus, however, I did not succeed in getting a single specimen. Liberal 

 rewards offered in Key West to the fishermen, expeditions in the Physalia to the neigh- 

 boring keys, and as unremitting a search as the climate permitted alike failed to procure 

 a single individual of this fish. The fish has been reported from Key West, but the 

 native fishermen there agree that it is not often found on the Florida Keys, and is 

 more abundant on the west coast of Florida than anywhere else that they know of. 

 Mr. C. F. Silvester, who is working in collaboration with me on the electric organs of 

 Astroscopus, has, however, secured three specimens of the fish this summer at Beau- 

 fort, North Carolina. 



Reef-collecting on the Tortugas affords a wonderful opportunity. No one who has 

 not waded on a coral reef can imagine the wealth of life found there. This is not 

 apparent from a surface view, however, as the coral reef fauna, with a few exceptions, 

 is hidden in the many crevices of the rock. In general the fauna was of two distinct 

 kinds. On the reef south of Garden Key an outer fauna was to be found on the 

 south side, where the exposure was toward the ocean, while on the northwest side a 

 different assortment of animals was to be found on the reef in the quieter and shallower 

 waters of the lagoon and channel. 



The pelagic surface collecting was grand, and more can be learned of this from 

 the report of Dr. Mayer and those who followed it up. Pterophryne was the one form 

 that I sought and I secured many specimens in person and from the other collectors 

 who brought them in. 



Among other features of interest were the swarming of the Atlantic Palolo worm 

 on July II and 12, and of which many of us got series of eggs and embryos, and the 

 frequent nesting of the turtles on the beach at night. For one working on the em- 

 bryology of the reptilia this would be an ideal place to spend the time from May until 

 September. 



Dr. C. H. Edmondson presents the following preliminary report upon 

 his extensive collection of Protozoa : 



Preliminary Report by C. H. Bdmondson. 



From June 20 to July 20, 1906, it was my privilege to pursue a systematic study of 

 the marine protozoa which inhabit the waters in the vicinity of the Biological Laboratory 

 of the Carnegie Institution at the Tortugas. This region is very rich in fauna of the 

 unicellular type. All classes and subclasses of protozoa are well represented, the habitats 

 being quite varied and the natural conditions favorable for their existence. 



It would be difficult to find a more favorable environment for certain forms of marine 

 protozoa than that which is furnished by the moat which surrounds the ruins of Fort 



