METKIDIUM. 



11 



mf> 



tacles, at first only few in number, are in fact so many extensions 



of the inner chambers, gradually narrowing upward till they 



form these delicate hollow feelers which make a soft downy fringe 



all around the mouth. (Fig. 7.) They do not start abruptly from 



the summit, but the upper margin p,,, , 



of the body itself thins out to 



form more or less extensive lobes, ' 



through which the partitions and 



chambers continue their course, 



and along the edge of which the 



tentacles arise. '^-^ _ 



The eggs are not always laid in 

 the condition of the simple planula ^~^ 

 described above. They may, on the » 

 contrary, be dropped from the par- '''/m' 



ent in different stages of develop- 

 ment, sometimes even after the tentacles have begun to form, as 

 in Figs. 8, 9. Neither is it by means of eggs alone that those 



Fie- 8. Fix. 9. 



./i'l'nfrtili 



animals reproduce themselves ; they may also multiply by a pro- 

 cess of self-division. The disk of an Actinia may contract along 

 its centre till the circular outline is changed to that of a figure 8, 

 this constriction deepening gradually till the two halves of the 8 

 separate, and we have an Actinia with two mouths, each stir- 

 rounded by an independent set of tentacles. Presently this sepa- 

 ration descends vertically till the body is finally divided from 



Fig. 7. View from above of an Actinia with all its tentacles expanded ; o uioutli, b crescent-shaped 

 folds at extremity of mouth, a a folds round mouth, t t t tentacles. 

 Figs. 8, 9. Young Actiniae in different stages of growth. 



