238 HISTORY OF BRITISH ZOOPHYTES. 
the testacea, fall a prey to the Actinia.”—“ The remarkable 
voracity of this creature warns the naturalist to beware of its 
presence among his collections, otherwise they shall as- 
suredly perish. Simple contact of the tentacula is the pre- 
lude of destruction. Some animals, as if conscious of their 
inevitable fate, seem paralysed by the touch, and yield 
without a struggle. Others, whose size and strength 
should ensure indemnity, are held in its relentless grasp ; 
the tentacula crowding faster and faster around, until the 
victim is speedily swallowed alive.” Sir John says, that he 
has no proof that the Actinia is victorious in consequence of 
discharging some deleterious fluid on its living prey, as 
many naturalists have supposed; and he gives it as his 
opinion, that in many cases it is quite evident that superior 
power is the only means employed for victory. Dr. John- 
ston, however, holds a different opinion, founded on ob- 
servations made by acute naturalists. ‘To disable the 
animal and render its struggles for escape unavailing, the 
class is furnished with poison-vesicles and spicula, similar 
to those which have been described as existing in the ten- 
tacula of the Hydra.” These organs were first discovered, 
I believe, by M. Quatrefages, but they have been described 
also by Wagner and Erdl. They are little elliptical capsules 
