228 ZOOPHYTES. 



side to side, and evincing motions quite different from the common ten- 

 tacular action. 



It is generally, though not invariably, at night, that a single tentacu- 

 lum shews this remarkable change. From its ordinary extent of about 

 half an inch, it enlarges to gigantic dimensions, sometimes becoming four 

 times as long, greatly thicker than usual, and distended to transparency. 

 It is then seen rising from among the rest, curving over to the opposite side 

 of the disc, and as if searching around. Thus it continues for a certain 

 period, when it is reduced to its wonted dimensions, like the remainder. 



None of the Scotish Actiniae, one excepted, have tentacula equal to 

 those now described. That species is said to want the faculty of with- 

 drawing them when extended, of which I have never had a specimen suf- 

 ficiently vigorous to enable me to judge. But from those falling into my 

 possession, they seem to exceed the size of the tentacula of the present 

 species. 



The species now named ewplorator, is prolific. Above sixty young 

 were produced during the course of a night, in a vessel containing two 

 small specimens. The young are usually pure white, and large in propor- 

 tion to the parent. 



Perhaps these animals breed throughout a considerable portion of 

 the year. 



The Actinia ewplorator is strictly of nocturnal habits. It stretches 

 itself up so as to become as tall as possible at night, which perhaps indi- 

 cates its natural abode, as deep in the crevices of the rocks, from whence 

 it rises for opportunities of capturing its prey. 



Plate XLVI. Fig. 11. Actinia explorator. 



§ 6. Actinia lacerata — The Ragged Actinia. — Plate XLVII. 

 Figs. 12, 13, 14, 15, lb', 17. — Amidst the numerous embarrassments ob- 

 structing the discrimination of species and varieties of the Actinia, it is . 

 fortunate to meet certain immutable features, so prominent as to distin- 

 guish some of them, so definitely from all others, as to leave no liability 

 to error. 



