466 THE MICROSCOPE, 



longitudinal set : both are flattened, and exhibit no tranrt- 

 verse striation. In some Actinice, such as A. 7nes,emhryan- 

 ihemiim, bright blue sacs are placed at the edges of the oral 



Fig. 231. — Hydra, loiih tentacles displayed and magnified, adliering to a stalk of 



Anacharis alsinaMrum. 



disc, while in A. gemmacea, A. sessilis, &c. clear spots are 

 scattered over the integument, which have been regarded 

 as apertures or tubercles; M. Hollard, however, states, that 

 these are imperforate Amjmllce, possessing a kind of bila- 

 biate mouth, surrounded by a sphincter-like arrangement of 

 muscular fibres. Any foreign body introduced into these 

 ampulla3 is seized and forcibly held ; or if the finger be 

 placed within reach, it gives the sensation of a very fine 

 rasp passing over it. The margins of the radiate tentacles 

 of the young animal are surrounded by cilia ; the gastric 

 epithelium is likewise ciliated, and doubtless secretes a 

 powerfully solvent fluid. The majority of the Actinice 

 are oviparous, the young being developed from ova within, 

 and evacuated by the mouth : they are also capable of 

 mrdtiplication by budding, and occasionally by fission, 

 while their power of restoring themselves after muti- 



