Contents 



PAGE 



Introduction . . . . . . . .11 



Classification . . . . . . . 13 



Asteroidea ........ 19 



External Structure . . . . . .20 



Internal Structure . . . . . -25 



Habits ........ 28 



Food ........ 29 



Natural Enemies . . . . . . -32 



Damage to Oysters and Other Mollusks . . .33 



Rate of Growth . . . . . . .40 



Migration ........ 43 



Variation in Number and Arrangement of Rays . . 43 



Regeneration . . . . . . -45 



Reproduction ....... 48 



Development ....... 52 



Key to Species ....... 58 



Asterias forbesi . . . . . .59 



Asterias vulgaris . . . . . .61 



Asterias tenera . . . . . .63 



Henricia sanguinolenta . . . . -65 



Ophiuroidea ........ 67 



Structure ........ 68 



Habits ........ 73 



Food ........ 75 



Reproduction . . . . . . .76 



Development . . . . . . -77 



Key to Species . . . . . . -79 



Ophiura brevispina . . . . . -79 



Ophiopholis aculeata . . . . .80 



Amphipholis squamata . . . . .81 



Amphioplus abditus . . . . .82 



Amphioplus macilentus . . . . .84 



Echinoidea ........ 85 



Structure . . . . . . . -85 



Habits ........ 97 



Reproduction . . . . . . .100 



Development ....... 100 



