Nos. 620-621] THE HAWAIIAN CORAL REEFS 



The fauna which inhabits the innumerable small cavi- 

 ties in the coral, and which drills countless tunnels 

 through the soft rock, is of much interest. This fauna 

 comprises chiefly the worm-like animals or sea-worms. 

 Important groups are Turbellaria, Nemertinea, and An- 

 nelids. Some species creep about in the interstices; 

 others construct covered passageways on the surface of 

 the coral. Others burrow in the sand and mud on the 

 floor of the lagoon. Some tunnel deviously through the 

 coral rock itself. Many of the sea-worms are brightly 

 colored. Little is known concerning the relationships or 

 life-histories of the Hawaiian forms. Nereis, Serpula, 

 Terebella, Tubifex, Sipunculus, and Echktrus are charac- 

 teristic annelid genera. 



The true corallines {Polyzoa) or sea-mats bear a close 

 resemblance to the hydroid zoophytes, and only upon 

 microscopic inspection show that their organization is 

 much higher than that of the hydroids. The skeleton is 

 not exclusively calcareous ; in many forms it is chitinous 

 or even gelatinous. These corallines are abundant on 

 the Hawaiian reefs. 



The true starfishes, Asterioidea, are comparatively rare 

 on the reefs themselves, although fairly common in the 

 offshore waters. The brittle-stars, Ophiuridea, are the 

 common reef forms, and lurk in every cranny. The Alba- 

 tross expedition collected 60 Hawaiian species of true 

 starfish during its dredging operations in the island chan- 

 nels ; they were taken at depths of 60-6,000 ft. These 

 represented 46 genera and 20 families; 52 species were 

 new to science. According to Bryan, 



Large specimens of an eight-rayed starfish, Luidia hystrix, are occa- 

 sionally captured at Pearl Harbor. They are often a foot and a half 



in the coarse green sponges in Kalihi Bay and at Pearl Harbor. A 

 small, stiff, irregularly developed, pink, leather-like species, Linckia sp. 

 without spines, is occasionally found crowded into small holes in the 

 coral reef. 



The common brittle-star, Phicema sp., is blue-black in 

 color, with small body and long snaky arms. It is gre- 



