192 CARNEGIE INSTITUTION OF WASHINGTON. 



animals, and he visited the island of Banda where he obtained mater- 

 ial from the large luminous organ of a fish which is used as bait in 

 this region. 



Professor Ulric Dahlgren also continued his studies of the electric 

 organs of fishes, using specimens of Gymnotus which had been collected 

 in British Guiana by Dr. William Beebe. 



Accompanied by Captain Potts, the Director attended the Inter- 

 national Scientific Congress of the Pan Pacific Union at Honolulu. 

 This meeting afforded an exceptional opportunity for discussing prob- 

 lems of the coral reefs of the Pacific with experts such as Andrews, 

 Hedley, and Vaughan, from Australia and America. 



We found that the reefs of Oahu Island lack the lithothamnion 

 ridge which is so well developed along the seaward edges of most 

 Pacific reefs. Due to the absence of a lithothamnion ridge, the reefs 

 are not well protected from the sea and resemble those of the Atlantic 

 in that their sea fronts do not overhang and they lack the well-defined 

 seaward precipices seen elsewhere in the Pacific. Indeed, these sub- 

 tropical reefs of Oahu are practically composed of only two genera 

 of corals. Pontes and Pocillopora, Acropora being absent. Actininians, 

 starfishes, mollusca, and halimeda are rare, but certain seaweeds 

 (such as Ulva) are more abundant than on the reefs of warmer parts 

 of the Pacific. 



The high cost of reconstruction prevented our opening the Tortugas 

 laboratory during 1920, but on the other hand, we took advantage of 

 the opportunity to complete the only intensive study yet undertaken 

 of a volcanic Pacific island and its reefs. While in itself the study of 

 so restricted a region may have little general significance, yet when 

 well-selected islands, as in the Society Group, Fiji, the barrier reef of 

 Australia, and the Philippines, have also been intensively studied and 

 compared, light may be thrown not only on the general theory of reefs, 

 but upon the genesis of the submerged platforms of the Pacific and the 

 relative age of the fossil-bearing limestones as compared with those 

 of Europe and America. The Department of Marine Biology is much 

 more than a mere laboratory, for it is essentially an agency for the 

 study of biological problems of all oceans. Starting with Tortugas as 

 a base, the logic of our studies has often led us far afield. Thus, the 

 work begun by Vaughan, Drew, and others upon the coral reefs of 

 Florida has been extended to the Pacific; Treadwell's work upon the 

 Eunicidse and Clark's upon the echinoderms of the Florida- West 

 Indian region made it desirable that their observations be extended 

 into the tropical Pacific. Longley's submarine studies of the coloration 

 of the reef fishes of Florida in relation to evolution and natural selection 

 would have lacked general significance had they not been carried on 

 also in the tropical Pacific. From the standpoint of zoology, paleon- 

 otlogy, and geology, accurate comparisons between conditions in both 



