212 ANTHOZOA HELIANTHOIDA. 



pools of which it expands prettily and discloses its beauty. It 

 roots itself upon rocks and stones, and ranges from the line of 

 the recess of the tide to near that of high water. It is conse- 

 quently often left exposed to the open atmosphere, but it expands 

 only when covered with water. It never, so far as I have observed, 

 emits from the mouth, like the other species, any thread-like tan- 

 gled filaments ; nor does it seem to have the power of protruding 

 the membrane of the stomach in the form of vesicular lobes. 

 Gaertner says that "the colour of its body is always red in the 

 summer, but changes into a dusky green, or brown, towards the 

 latter end of autumn," a remark which certainly does not hold 

 good on the shores of Britain nor on those of Ireland. 



The number of marginal tubercles varies from eight only to 

 upwards of twenty. Professor Forbes says that they are sometimes 

 wanting. This variety may possibly be the Actinia rufa of Miiller, 

 and of those authors who have copied him ; but neither in his 

 figures nor description does Miiller make any mention of these 

 organs, and Rapp gives the species as distinct. The Actinia con- 

 centrica of Eisso (L'Europ. merid. v. p. 286), appears to be founded 

 on the azure-blue streaked variety, which is very pretty. Nor less 

 so is a small green variety, in which the body is covered with 

 golden-coloured dots arranged in longitudinal lines. 



The young differ from the adult only in having fewer tentacula, 

 which are at first produced in a single series. 



That our species is synonymous with the Entacmaea mesembry- 

 anthemum of Ehrenberg (Corall. p. 36) is very doubtful. 



The blue eye-like tubercles on each side of the mouth become 

 visible only when the labial membrane is extruded. They vary in 

 colour in the different varieties, and are never absent. They are 

 common to the genus, (at least, Mr. Cocks has found them in all 

 the species that have come under his notice,*) but they vary in 

 hue, and a little in the depth of their colouring. Their function is 

 uncertain. Mr. Cocks inclines to believe that they are organs of 

 vision, for in a subdued light he found that Actinia mesembryan- 

 themum left them exposed, but bent the tentacula over them, as if 

 to shade them, when exposed to the bright rays of the sun. (Fig. 45.) 

 To confirm Mr. Cocks' conjecture it would be necessary, I think, to 



* Grube discovered these organs, and called the species in which he observed 

 them Act. bimaculata. Actin. p. 4, fig. 4. This seems to me to be a variety merely 

 of Act. coriacea. 



