42<i 



THE AMERICAN NATURALIST [Vol. LII 



troduce and establish the valuable species from other 

 parts of the world. All of the commercial sponges be- 

 long- to the two genera Enspongia and Eippospongia, 

 which do not occur on the Hawaiian reefs. Such an en- 

 terprise, if undertaken with thorough scientific supervi- 

 sion, would unquestionably meet with success. There are 

 many areas along our reefs where the sponges could be 

 established. With adequate labor and marketing* ar- 

 rangements a steady development of the industry would 

 be assured. 



It is of interest to note that of the fresh-water sponges, 

 Spm,(/in>H(i>, a group which is widely distributed in -all 

 part* of the world, no representatives have been taken 

 in the Hawaiian Islands. 



Jellyfish are of casual occurrence along our reefs. The 

 smaller forms are chiefly Hydrozoan medusa?; the larger 

 ones are Scyphozoans. A relatively few species are 

 known and the life-cycles of these are not known in detail. 

 A number of the tiny species are phosphorescent, and on 

 clear nights when the sea is calm and other conditions are 

 favorable, they give beautiful luminous effects. In pad- 

 dling along the reef in an outrigger canoe, on such a night, 

 the paddles, at every stroke, drip with tiny stars. Many 

 of the larger species have gonads, tentacles, radial canals, 

 or other organs brilliantly pigmented. 



The large forms attain diameters of 8-12 in. and some- 

 time- appear in great numbers in quiet, protected waters. 

 Pearl Harbor, for example, which is almost wholly land- 

 locked, is a favorite habitat. At low tide, in other parts 

 of the islands, along the coral beaches one sometimes finds 

 great numbers of jellyfish stranded and slowly deliquesc- 



In addition to the true jellyfish the reefs support a rich 

 hydrozoan or marine hydroid fauna. The littoral species 

 have not been studied taxonomically ; the Albatross collec- 

 tions were made at depths of 60-3,000 ft. These latter 

 comprised 49 species, representing 27 genera and 11 fami- 

 lies. The shallow-water zoophytes or hydroids are abun- 



