I 



SEA ANEMONES. 203 



where the vast freshwater current of the Mississippi debouches into 

 the sea, they are unknown. It is principally on the north coast and 

 upon the eastern flanks of the chain of West Indian Islands that the 

 coral reefs show themselves in these regions. 



The AcTiNiDiT:. 



Here we leave the group of polyps which form united families. 

 The Sea Anemones, of which the genus Actinia is the type, consist of 

 Zoa?it/iaria, which produce no true polypidom, that is to say, of 

 polyps whose integument remains always soft, and in whose interior 

 no calcareous plates are produced. This order is usually divided 

 into two groups — that in which the base is adherent at pleasure, as in 

 Actinia, and that in which the base is not adherent, as in llyanthus. 



The modern aquarium enables the spectator to witness man)- 

 wonderful sights. Adherent against the transparent crystal walls 

 of the basin, he observes living creatures of the most brilliant shades 

 of colour, and more resembling flowers than animals. Supported 

 by a base and cylindrical stem, he sees them terminate like the 

 corolla of a flower, as in the petals of the anemone : these are the 

 animals we call Sea Anemones— curious creatures, which, as all per- 

 sons familiar with the sea-shore may have observed, are at one time 

 seen suspended from the rocks, and again buried at the bottom of 

 the sea. These charming and timid creatures are also called Actinia, 

 as indicating their disposition to form rays or stars, from the Greek 

 d/cris, a ray. 



The body of these animals is cylindrical in form, terminating 

 beneath in a muscular disc, which is generally large and distinct, 

 enabhng them to cling vigorously to foreign bodies. It terminates 

 above in an upper disc, bearing many rows of tentacles, which difier 

 from each other only in their size. These tentacles are sometimes 

 decorated with brilliant colours, forming a species of collar, consisting 

 of contractile and often retractile tubes, pierced at their points with 

 an orifice, whence issue jets of water, which are ejected at the will of 

 the animal. Arranged in circles, they are distributed with perfect 

 regularity round a central mouth. These are their arms. 



The mouth of the Sea Anemone opens among the tentacles. 

 Oval in form, it communicates by means of a short tube with a 

 stomach, broad and short, which descends vertically, and abuts by a 

 large opening on the visceral cavity, the interior of whicli is divided 

 into little chambers. These chambers are not all of the same dimen- 

 sions ; in parting from the cylindrical walls of the body, they advance, 



