ON POLYPS. 



Fig. 11. 



Fig. 12. 



Although the genera composing this division are exceedingly 

 numerous, and vary much in their external characters, they will 

 be found more or less to conform in the essential points of their 

 organization with the subject which we have chosen as the type of 

 this extensive tribe, and of which, being common upon our own 

 coasts, the reader will have little difficulty in procuring specimens 

 for examination. 



(54.) The body of an 

 Actinia when moderately 

 expanded, (fig. 11?) is a 

 fleshy cylinder, attached 

 by one extremity to a 

 rock, or some other sub- 

 marine support ; whilst 

 the opposite end is sur- 

 mounted by numerous 

 tentacula, arranged in se- 

 veral rows around the oral 

 aperture (fig. 1) . When 

 these tentacula are expand- 

 ed, they give the animal 

 the appearance of a flower, 

 a resemblance which is 

 rendered more striking by 

 the beautiful colours which 

 they not unfrequently as- 

 sume ; and hence in all 

 countries they have been 

 looked upon by the vulgar 

 as sea-flowers, and distin- 

 guished by names indica- 

 tive of the fancied resem- 

 blance. Their animal na- 

 ture is however soon 

 rendered evident by a little attention to their habits ; when 

 expanded at the bottom of the shallow pools of salt-water left by 

 the retreating tide, they are seen to manifest a degree of sensibility, 

 and power of spontaneous movement, which we should little an- 

 ticipate from their general aspect. A cloud veiling the sun will 

 cause their tentacles to fold, as though apprehensive of danger 

 from the passing shadows : contact, however slight, will make 



