428 THE AMERICAN NATURALIST [Vol.LII 



surf. The colors most frequently observed are shades of 

 tan, olive and purple; some forms have tentacles which 

 are beautifully pigmented. The size varied from species 

 so minute as to almost escape detection up to fine showy 

 forms 1-2 in. in diameter. They form considerable colo- 

 nies, sometimes covering areas of several square feet. 

 Isolated individuals, particularly of the larger species, 

 are not rare. Usually their rosette of tentacles and bril- 

 liant color renders them quite conspicuous, but many 

 kinds are embedded more or less completely in the sub- 

 stratum, and upon the slightest alarm contract into shape- 

 less lumps, and are thus easily overlooked. 



The Ctenophora have about 20 known species in 

 Hawaiian waters, but these are so rare and fragile that 

 they are practically unknown to the reef-collector. They 

 are all pelagic, delicate, transparent creatures, with long 

 tentacles and peculiar comb-like locomotor organs. As 

 they swim gently through the sunlit waters their trans- 

 parent bodies and tentacles yield beautiful iridescent re- 

 flections. Hormiphora, Cestus, and Beroe are well- 

 known genera. All the members of this highly specialized 

 group are solitary and do not form skeletons. 



