156 ANTHEAD.E. 



from the bottom of the tentacle, and passes up very slowly, 

 occupying many hours. 



When once it has adhered, and recovered its health, its 

 elegant postures and forms, and its remarkable versatility, 

 make the Aiptasia an interesting occupant of the aquarium. 

 It marches from stone to stone, and around the walls of its 

 tank, frequently creeping to the top of the water, and ex- 

 panding its base upon the surface, almost or even quite 

 floating, while the disk and tentacles, widely expanded, are 

 suspended below in mid-water. In these habits we see a 

 close resemblance to Anihea cereus, as also in the texture 

 of the body, and in the tentacles, which in both genera 

 are lined with a profusion of dark-brown pigment-granules, 

 which are readily separated. 



Occasionally I have noticed that it has the power of 

 adhesion to foreign bodies by the general surface of the 

 column ; a habit common to several of the UyantMdce, (as 

 the Halcampce, for example,) but which, I think, is not 

 possessed by Anihea. 



When in full vigour it towers up to the height repre- 

 sented in the figure, when, with its ever-twisting tentacles 

 and semi-pellucid tapering column, it is a very elegant 

 object. When thus greatly elongated, the loop-holes are 

 plainly seen with a lens. I have been able to thrust the 

 point of a fine needle into one and another of these orifices, 

 without meeting any resistance ; and, by using great care, 

 without the animal's being conscious of it ; when it did feel 

 the touch, however, it suddenly contracted. 



Under these and similar irritations, it contracts in length 

 by successive spasmodic jerks, but makes no attempt to 

 roll in the margin of the disk, or to hide the tentacles in 

 any way. Yet it has the power of involving the disk. It 

 feeds greedily, throwing the margin in folds over the mouth. 

 After a full meal, I have seen it take the shape of a ripe 



