THE AXLMAL LIFE OF THE GROUP. 487 



They are said to feed ou seaweed and also on dead fish and decaying matter of 

 various Ivinds. The large purple-black species,^ with long, slender, awl-shaped 

 spines, prefers the deeper water in the holes toward the outer edge of the reef. 

 With it occurs a similar species " in which the long spines are banded gray and 

 black. Both species are known as Wana, or sea eggs, and ave much sought 

 for by the Hawaiians. who arc very fond of them. 



The spines of the wana are both sharp and brittle and intliet a serious 

 wound. If the native fisherman is so unfortunate as to be in.jured l)y one he 

 will bite the wound savagely in order to grind the spine into fine fragments 

 so that the pieces will come out later on with the pus. 



The beautiful clnb-spined " urchins are quite common at certain places 

 ou the reef, and are often ou exhibition in the Aquarium in Honolulu. They 

 are as large as the preceding species, but are a reddish-brown color, and the 

 spines are heavy and blunt and imperfectly triangular. 



A curious rough rock ui'cliin.^ the haukeulvc, has the spines short and 

 blunt over the back, but long and dull-pointed about the edge. They are 

 fond of the rough sea and adhere to the black lava rocks exposed to the full 

 dash of the waves. 



A large heart-shaped urchin,'' covered with line short brown hair-like 

 spines, is known as the sea biscuit or heart-urchin. (,)ther forms are occasion- 

 ally collected in shallow water. Imt the majority of the Echinoidea are found 

 in deeper water offshore. The number of species inhabiting the Hawaiian 

 waters is not determined, but it is known to be a rich fauna, there being a 

 number of rare species. 



St.vrfishes. 



While the true starfishes'" are fairly connnon in the deeper' water off- 

 shore, they are not very abundant on the coral reef. As a matter of fact, 

 it is a great find to collect a specimen of any size from the reefs about Oahu. 

 It is necessary to imderstand at this point that in the typical starfish the arms 

 are usually, though not always, five in number and that, as a rule, they are not 

 sharply marked oft' from the central disk, as is the case with the brittle-star- 

 fish," two or three species of which are plentiful in shallow water. In 

 the true stars the feet are located in a definite groove, while in the brittle stars 

 the grooves are not present. 



The connection of the fe^^ with the wati'r-vascular system is vei-y inter- 

 esting. On the back between two of the arms may be seen a curiously rough- 

 ened plate 1- that in reality is a sieve through wliieli the water is strained before 

 it enters the system. Connected witli this sie\-e-iike liody is the stone-canal. 

 It runs downward and connects with the ringed-canal which encircles the 

 mouth ; from this canal five radial canals, one for each arm, pass outward 

 just above tlie amliulaeral gi-ooves. The radial-canals give off side branches 



i Podfiphora prilifr 



