82 VIGNETTES FROM INVISIBLE LIFE. 



sever themselves from the body of the parent, 

 and begin life on their own account. Another 

 mode of reproduction is by the formation of sper- 

 matozoa and ova. Both are formed on the same 

 body, in small conical and sac-like projections. 

 When maturity is reached, the sperm-sac bursts, 

 and the contents, becoming liberated, fertilise the 

 ovum, very much after the manner accomplished 

 by the pollen of flowers. After being fertilised 

 the ovum becomes invested with a thick and hard 

 covering, drops off, and remains thus protected 

 at the bottom of the water through the winter ; 

 and on the return of spring from these seeds 

 or eggs new Hydrce are reproduced. Thus the 

 Hydra, though differing materially from vegetable 

 forms of life, yet shows some striking likenesses to 

 them, especially in its reproductive processes i.e., 

 buds, cuttings, and covered seed which germinates 

 apart from its parent, &c. 



Though not a displeasing object to the eye, but 

 on the contrary very graceful in form and motion, 

 the Hydra is yet one of those beings from which 

 the gentler sentiments recoil. Their poisonous 

 stings, their coiling arms enveloping animals 



