Nos. 620-621] THE HAWAIIAN COEAL BEEFS 



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dant in all protected situations ; many forms also inhabit 

 the surf -beaten rim. Sertularia. Phi miliaria and Cain- 

 pcmidaria are well-known genera. The species are all of 

 small size and superficially resemble in habit, color and 

 habitat the more delicate marine algae. 



The false corallines or HydrocoraUiua are also very 

 abundant and have played an important role, as have the 

 coralline alga?, in the construction of the Hawaiian reefs. 

 These colonial animals resemble delicately branching 

 corals; their bleached and rather fragile skeletons are 

 common on the beaches. When alive the corallines are 

 of various tints of pink, orange and salmon, and add 

 bright touches of color to the brilliant ensemble of the 

 reef. The HydrocoraMince occur only in tropical seas; 

 JliUepora and Stylaster are typical genera. 



That remarkable order of free-floating colonial hy- 

 droids. the Sipliottophora, is well represented in all trop- 

 ical waters, and has numerous forms in the Hawaiian 

 marine fauna. This group exhibits the greatest diversity 

 of form. The common "Portugese man-of-war," Phy- 

 salla utriculua, with its brilliant peacock-blue float and 

 long retractile tentacles, is abundant along the reefs and 

 shallows, and like the jellyfish, is often cast ashore in 

 enormous numbers. The tentacles contain powerful bat- 

 teries of stinging capsules ; the wounds are intensely pain- 

 ful, and so this lovely evanescent creature is dreaded by 

 bathers. Other well-known genera are Hahstemma, 

 Diphyes, Par pit a and Vellelo. Par pit a pad fica, the sea- 

 money, is a beautiful blue-fringed disc about H in. in 

 diameter. Vellela pacifica is also abundant at certain 

 seasons. It resembles Physalia, but has much shorter 

 tentacles. 



Sea-anemones, Actiniaria, are abundant along the 

 Hawaiian reefs, but no taxonomic studies have been made. 

 A number of species inhabit the inshore pools whose 

 water- are periodically renewed by waves or tides; others 

 may be found on the floor of the lagoon, and still others 

 on the protected sides of rocks which stand in the heavy 



