58 ANTHOZOA. 



we have yet encountered. In the Actinice the tentacles 

 are very numerous, and ranged in several circles round 

 the mouth. When expanded, being often of gay colours, 

 they so much resemble composite flowers, such as the 

 daisy, the marigold, and others, as to have obtained their 

 names for different species, and the term " animal flowers " 

 for the entire group. When expanded and viewed in 

 profile, the form of an Actinia is that of a short, broad, 

 cylinder, with the tentacles radiating from the upper 

 margin (Fig. 40), the base being somewhat dilated. But 

 when the absence of light or water, or any other cause, 

 induces them to repose, the tentacles contract, and the 

 upper part of the body, by a partial inversion, closes over 

 them, leaving no trace of the place where they disappeared 

 except a wrinkled depression in the centre. In this con- 

 dition their shape is, more or less, that of a bell, as may 

 be seen in the next figure (Fig. 40). 



When still more firmly closed, the creature looks like 

 nothing but a rounded lump of fleshy substance, plastered 

 on the rock (Fig. 41, 2) ; but as the animal again expands, 

 the central opening at the top gradually widens, the 

 margin slowly rolls back, and the tentacles it concealed 

 begin to show their tips. As the expansion goes on, the 



FIG. 40. FIGUBE OF ACTINIA. 



tentacles continue to enlarge, and the margin to spread 



outwards, until, finally, the disk with the mouth in the 



centre is fully displayed, and the tentacles, like petals, 

 fringe it round. 



In the species delineated in the next figure, Actinia gemmacea, 

 there is an instinct displayed of a very admirable character. Such 



