ACTIXIAD^E : ACTINIA. 239 



which strikingly illustrates the futility of that classification which 

 mainly rests the distinction of its genera upon the number of these 

 circles .* 



The Actinise are very patient of injuries, and rival the Hydra in 

 their reproductive powers. They may be kept without food for 

 upwards of a year ; they may be immersed in water hot enough to 

 blister their skin, or frozen in a mass of ice and again thawed ; and 

 they may be placed within the exhausted receiver of the air-pump, 

 without being deprived of life, or disabled from resuming their usual 

 functions when placed in a favourable situation. If the tentacula 

 are clipped oif they soon begin to bud anew, and if again cut away 

 they grow again : so that " it seems these reproductions might 

 extend as far, or be as often repeated, as patience or curiosity would 

 admit." If cut transversely through the middle, the lower portion 

 of the body will after a time produce new tentacula " pretty near as 

 they were before the operation ;" while the upper portion swallows 

 food as if nothing had happened, permitting it indeed at first to 

 come out at the opposite end, "just as a man's head, being cut off, 

 would let out at the neck the bit taken in at the mouth," but which 

 it soon learns to retain and digest in a proper manner. In an ex- 

 periment of this kind, the upper half, instead of healing up into a 

 new basis, actually produced another mouth and tentacula ; so that 

 an animal was formed which caught its prey, and fed at both ends 

 at the same time ! If again the section of the body is made in a 

 perpendicular direction so as almost to divide it into two halves, 

 these halves unite again in a few days. If the section is complete, 

 two perfect individuals is the result ; and to complete the wonder, 

 if the body is torn away, and only a portion of the base remain, 

 from this fragment a new offspring will sometimes rise up to occupy 

 the place of its parent ! t Yet these creatures, almost indestructible 

 from mutilation and injury, may be killed in a few short minutes, 

 by immersion in fresh water. 



pleton in Mag. Nat. Hist. ix. 303 ; Harvey in ibid. n. s. i. p. 474 ; Rep. Ray Soc. 

 1845, p. 381. 



* Brandt. A Synopsis of his System is given by Blainville. Actinologie, p. 666. 



f Dicquemare in Phil. Trans, abridg. xii. 640, &c. ; xiv. 129. Yet, according to 

 the same excellent naturalist, a wound or rent of the basis of an Actinia often proves 

 fatal, xiii. 637. 



