THE ANIMAL LIFE OF THE GROUP. 485 



up on the tines of a rake. They are much sought by zoologists owing to their 

 primitive chordate characters, but uninformed collectors would place them 

 at once among the worms. If specimens are carefully collected and placed in 

 a jar of sea water and sand, they make interesting exhibits in the schoolroom 

 or laboratory. 



CHAPTER XXXVII. 

 PLANTS AND ANIMALS FROM THE CORAL REEF: PART TWO. 



The Hawaiian reefs abound in representatives of the phylum,* including 

 such odd and diverse animals as the starfish, sea-urchins, brittle-stars and 

 the sea-cucumbers. The curious bleached white skeletons of the sea-urchins, 

 with the beautiful lace-like pattern pierced in fine holes over the biscuit-shaped 

 shell or test, are among the objects jjieked up with shells and seaweed on the 

 sand beach. They are hardly to be recognized, however, as the remains of 

 the spiny sea-urchin so often stepped on by incautious bathers. They are the 

 "hedge-hogs" of the sea, since the numerous calcareous plates forming the 

 shell are covered in the several species with variously-shaped spines. These 

 spines serve the ina, as the sea-urchins are called by the natives, as a means of 

 protection, and in certain species they are used to assist in boring the burrows 

 often inhabited by them in the solid rock below low-tide. 



Sea-L^rciiins. 



The common forms are a black species,- or ina eleele, and a whitish 

 form,-' ina keokeo. They both are very plentiful on the coral reefs about 

 Honolulu and are gathered and eaten by the natives. If one is taken alive 

 from its hiding place beneath the loose stones on the outer edge of the reef and 

 examined, the spines will be found to move on a ball-and-socket joint. The 

 tubercles on the test forming the attachment for the spines are arranged 

 mainly in five broad bands extending from the top round to the bottom or oral 

 side. Alternating with these are five narrow bands bearing fewer tubercles, 

 but pierced by the small holes arranged in rows as referred to above. Through 

 these holes pass numerous curious tube-feet, each provided with a sucker on the 

 end. These are therefore the walking bands. •• The vent is situated in the 

 summit or aboral side of the test. The membrane on the bottom or flat side 

 surrounds the mouth, from Mdiich proti'ude the tips of five pointed teeth. If 

 the membrane is removed a curious conical structure will be seen commonly 

 called Aristotle's lantern. 



One of these animals dropjied into a salt-water a(iUMrinin will prove an 

 interesting object. Placed in water, the tube walking feet expand and the 

 creature will slowly glide along, oi- if placi'd on its back it will right itself. 



