THE AXMAL LIFE OF THE GROUP. 477 



The coral reefs of the Pacific have been much studied by oceanographers, 

 zoologists and geologists who have sought to wrest from them something of the 

 history of the formation of the islands in this vast ocean. The geologic sig- 

 nificance of the Hawaiian reefs has been pointed out in another connection. 



While biit few have ever attempted to list the various species of corals 

 found here, their study was first undertaken seriously long ago. In 1840-41 

 the renowned geologist James D. Dana, whose epoch-making book on the coral 

 islands is a scientific classic, visited Hawaii and examined the reefs, as a 

 member of the scientific staff of the United States Exploring Expedition. As 

 a result a dozen of the more common shallow-water forms were described as 

 new by him in a portion of the report of that expedition, published in 1846. 

 Since then others have added to the list, but it remained for my friend, Dr. 

 T. W. Vaughan, to give the subject the attention it deserves. As a result of his 

 labors, based primarily on the collections secured by the Albatross expedition 

 in 1902, but supplemented by a large collection of shallow-water coral secured 

 by members of the staff of the Bishop Museum, we now have available for 

 the specialist a handsome monograph in which representatives of fifteen fami- 

 lies, including tliirty-four genera, to which, according to that author, are re- 

 ferred one hiuidrcd and twenty-three species, varieties and forms. Of that 

 number more than three-fifths are described and figured for the first time. 

 Some idea of the richness of the coral fauna of any given locality can be 

 gathered from the fact that the reef and shallow waters along the south side 

 of Oahu, but especially at Waikiki, yielded examples of thirty-four of the 

 species enumerated. 



While a single species'-'* of mushroom-like coral was brought to the sur- 

 face by the dredges of the Albatross from the great depth of eleven hundred 

 and fifty fathoms, the great majority of the forms, seventy-seven in number, 

 occur in water from one to twenty-five fathoms in depth. Of the fourteen 

 genera that occur in this shallow water zone throughout the group, ten were 

 collected on reefs of Oahu fi-om Pearl Harbor to Diamond Head. Represen- 

 tative specimens of the common genera from this locality are here figured. 

 The figures will aid in the generic determination of such forms as are most 

 liable to be collected, but definite identification of the species and the almost 

 numberless forms of certain species is in many eases almost impossible, even 

 when the type specimens can be seen. 



The genera occurring in the shallow water about Oahu may be regarded 

 as the living representatives of the reef-building forms that for thousands 

 perhajis niillioiis of years have been building the lime I'lirk tluit fringes the 

 islands. 



Of the several genera Porites, the pohaku puna of the natives is the most 

 abundant and is represented b>' the largest number of forms. The Pocillopora are 

 perhaps next both in size and aljundance, and like the preceding genus, they 

 range through an extensive list of varied forms. Monti/jnra is next in abnn- 



^ Bathj/acfes hawaii 



