RHOD ACTINIA. 13 



motion, by means of the expansion and contraction of this foot- 

 like disk. 



The Actiniae are extremely voracious ; they feed on mussels 

 and cockles, sucking the animals out of their shells. When in 

 confinement they may be fed on raw meat, and seem to relish it ; 

 but if compelled to do so, they will live on more meagre fare, and 

 will even thrive for a long time on such food as they may pick 

 up in the water where they are kept. 



Rhodactinia. (Rhodactinia Davisii AG.) 



Very different from this is the bright red Rhodactinia (Fig. 

 10), quite common in the deeper waters of our bay, while far- 

 ther north, in Maine, it occurs at low-water mark. Occasion- 

 ally it may be found thrown up on our sandy beaches after a 

 storm, and then, if it has not been too long out of its native 

 element, or too severely buffeted by the waves, it will revive on 

 being thrown into a bucket 

 of fresh sea-water, expand 

 to its full size, and show all 

 the beauty of its natural col- 

 oring. It is crowned with a 

 wreath of thick, short tenta- 

 cles (Fig. 10), and though so 

 vivid and bright in color, it 

 is not so pretty as the more 

 common Actinia marginata, 

 with its soft waving wreath of 

 plume-like feelers, in compar- 

 ison to which the tentacles of the Rhodactinia are clumsy and 

 slow in their movements. 



All Actinias are not attached to the soil like those described 

 above, nor do they all terminate in a muscular foot, some being 

 pointed or rounded at their extremity. Many are nomadic, wan- 

 dering about at will during their whole lifetime, others live 

 buried in the sand or mud, only extending their tentacles beyond 

 the limits of the hole where they make their home ; while others 

 again lead a parasitic life, fastening themselves upon our larger 



Fig. 10. llhodactinia Davisii Ag. ; natural size. 



