ACTINIA. 233 



induced to conclude that the vascular young found in the same vessel, 

 have originated unobserved from the same source. 



The adult seldom shifts its position; it continues adhering many 

 months to the same spot, therefore, although profuse exuviation of the 

 upper parts takes place, probably very little skin separates from the under 

 surface. 



When the water proves vitiated, this Actinia, instead of closing it- 

 self up, or endeavouring to escape by quitting its place, merely stretches 

 itself as high as possible to shun the deleterious influence of the surround- 

 medium. 



Plate XLVII. Fig. 12. Actinia lacerata, the Ragged Actinia, adult. 



13. Embryonic fragments separating spontaneously from 



the mai-gin of the base, September 1 . 



14. The same farther advanced, September 17. 



15. The same, September 18. 



16. A portion of the base from which embryonic fragments 



are withdrawing, but still connected by a ligament. 



17. Corpuscula or gemmules produced in July, enlarged. 



§ 7. Actinia maculata — The Spotted Actinia. — Plate XLVIII. 

 Figs. 3, 4, 5. — All the preceding Actiniae have a general correspondence 

 in external shape, and it may be in general habits. When completely 

 displayed they rise as a cylinder, with a summit of expanded tentacula, 

 and an expanded base, both of more ample diameter than the body. But 

 the form of the present subject presents considerable difference, and its 

 habits, with its natural abode, seem to be also somewhat different. 



I have never seen the Actinia maculata but of a flattened figure, even 

 when displayed, and much more so than is incident to the others, for it 

 will be recollected that the flattening of the Actinia lacerata is consequent 

 on the contraction of all its parts. The favourite position of the present 

 subject is to remain permanently seated on the same shells that are usually 

 occupied by the hermit crab, with which the Actinia must be carried about 

 in its excursions. The base spreads over the surface, so as to be accom- 

 vol. n. 2 G 



