SE ASIDE STUDIES. 



315 



tion of an inch in diameter. Our most common kinds are from one to 

 two inches, and expand from two to four inches. Some of the tropical 

 kinds are a foot in diameter. 



Fig. 5. Cluster op Coral-Polyps (Asteroides 

 calycularis, Miine-Edwards) in various stages 

 of expansion. 



Fig. 6. Dead Cokal {Asteroides 

 calycularis, Milne-Edwards.) 

 The coral of Fig. 5. 



-c"fir_ c < v? 



\o 







w 



Fig. 7. Madrepore Coral (Madrepora aspera, Dana). Right-hand branches alive; the left, dead. 



The sea-anemones, whether in their natural home or in the aquarium, 

 are exceedingly interesting objects ; and in the latter place we can 

 study them to the best advantage. Carefully remove a dozen of them 



Fig. 8. Dana's Astrangia (Astrangia Dance, Agassiz) : c, a growing cluster ; a, a single polyp 



enlarged ; b, the dead coral. 



