82 ZOOPHYTES. 



the mode whereby it multiplies its kind, with the view of explaining the 

 increment of the arborescent zoophytes by the latter, I shall offer a few 

 definite remarks on the subject. 



Propagation. — The faculty of perpetuating its race — that is, of beings 

 precisely similar to itself — resides in each individual of the Hydra tuba. 

 To that extent we would pronounce it a perfect creature of the same con- 

 sistence and form from its earliest origin as derived of a parent hydra ; 

 and its descendants, derived in the same manner, are identically so down 

 to distant generations. 



In as far as may be judged, the perpetuation of the species — that is, 

 of the hydraform species — is an irresistible result of mere existence, a con- 

 sequence over which the individual hydra is not known to have any con- 

 trol, more than the individual vegetable has over the swelling bud or ex- 

 panding blossom. Neither is it evidently dependent on age, at least in a 

 general sense ; for we can scarcely pronounce on that period when even 

 a nascent individual is immature. 



Let us assume, in the first place, an adult. If preserved in a suitable 

 situation, supplied with food, and its renovated element in purity, an em- 

 bryo speedily germinates from the side. 



Thence it is natural to conclude that a germ, or depositation of ele- 

 mentary matter, subsists somewhere in the flesli — that, generated within 

 as a compact substance, its way is made, by a regular process, to the ex- 

 terior, where it becomes visible as a rising prominence. 



Almost the whole of this animal's body is occupied by the stomach, 

 which swells from the disc to the apex when distended with food. All 

 reproductions or germinations necessarily ensue from its vicinity, and it is 

 singular how much propagation is promoted by abundant sustenance, as 



already noted. 



The embryo literally buds from the side of the parent as a simple 

 protuberance, frequently accompanied by a long fleshy spur with an en- 

 laro-ed extremity. Its use is uncertain ; nor is it permanent. But its ex- 

 istence seems solely dependent on the progress of reproduction ; and as the 

 early embryo advances to a later stage it disappears. This spur is previously 

 endowed with voluntary motion ; it curves and alters its direction readily, 



