THE ANIMAL LIFK OF TlIK (IKOI.P. 485 



up on tile tiiK's of a rake. They ai'e imicli sou^lil l)y zoiilonists owiiiu to IIhmc 

 primitive ehordate characters, but uuiuformed collectors Avould place them 

 at once amon^' the woi-ms. If specimens are cnrerully (-(jllected and placed in 

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

 or laboratory. 



CHAPTER XXXVII. 

 PLANTS AND ANIMALS FRO^r THE CORAL REEF: PART TAVO. 



The Hawaiian reefs aliound in representatives of the pliylum.' includinLi- 

 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 picked up with shells and seaweed on the 

 sand beach. They are hardly to l)e recognized, however, as the remains of 

 the spiny sea-urchin so often stepped on by incautious ])atlicfs. Tlioy arr the 

 "hedge-hogs" of the sea, since the numerous calcareous ])lates formiiiL: the 

 shell are covered in the several species Avitii 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-Urchins. 



The common forms are a black species.- oi- ina el eel e. and a whitish 

 form,'^ ina keokeo. They both are very {)lentil'ul on the coral n'vfs abt)ut 

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

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

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

 tubercles on the test forming the attachment foi' the spines are arrangecl 

 mainly in five broad bands extending from the io[) I'ound to the bottom or oral 

 side. Alternating with the.se are five narrow bands bearing fewei- tubercles, 

 but pierced by the small holes arranged in I'ows as referi-ed to above. Through 

 these holes pass numei'ous cui'ious tube-feet, each i)rovided 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 membfane on tlie boltoin oi' flat side 

 surrounds the i!U)uth, fi'oiii wliieji prolrude the ii|is ol' li\-e poinli'd leetli. If 

 the membi-ane is renuived a curious conical sli'ucture will be seen commonly 

 called Aristotle's lantern. 



One of these animals di'oiipeil into a salt-v.ater a(|uariuin will prove an 

 interesting object. Placed in water, tlie tube walking I'eet expand and tin 

 creatui-e will slowly glide along, or if placi-d on its back it will i-ieht itself. 



^ Erhinodcrmafa. • Echinomrira sp. ^ Echiiminctra sp. ' \ nil.nl.i.rnl n>u, 



