HYDRA. 83 



from being quite flexible. It is seen of various dimensions ; one half an 

 inch long, and of quantum equal to six tentacula, has issued from the base 

 of a young hydra still connected with the parent. 



In the course of a series of observations on the progress of reproduc- 

 tion, I detached an adult from its site, on April 23, and deposited it in a 

 watch-glass, where, owing to favourable circumstances, it soon adhered. 



In four days, a spur issued from one side of the base, and a large pro- 

 tuberance with a row of papillae, an originating embryo, was rising from 

 the other. — Plate XIII. fig. 3. Parent, a ; embryo, b ; spur, c. All as 

 on April 27. 



On May 2, these papillae had elongated into perfect tentacula, like 

 those of adults, when both the parent and the offspring were fed. — Fig. 4. 



Another protuberance on the opposite side of the parent was now 

 visible, either obscuring the spur or incorporated with it, which protube- 

 rance, gradually maturing as a young hydra, was fed on May 17 ; and the 

 subject, as consisting of three perfect animals and a spur, was delineated 

 on May 21. — Fig. 5. 



The parent and the progeny were still connected ; but in other three 

 days decisive maturity of the latter appeared by the separation and esta- 

 blishment of three members of the cluster as independent animals. 



It must be understood that, in earlier stages, the body of the parent 

 and the embryonic germination constitute a common integral mass ; but 

 as the uniting apex, or real basis of the embryo, is continually refining and 

 diminishing, it remains very slightly connected with the parent. Farther 

 security is therefore obtained by adhesion to some solid substance — here 

 the watch-glass ; then the offspring receding imperceptibly until united to 

 the parent only by a slender ligament, its rupture or disappearance sepa- 

 rates them for ever. 



About May 24, the three specimens, a, h, c, were ranged in a straight 

 line. At a previous period they would have been comprehended in a 

 spherical triangle. Two protuberances, e, f, appeared on the opposite sides 

 of the parent, a, with a spur from e. A prominence also rose from 6 ; 

 c showed nothing. But on May 29, a small hydra, d, which had origi- 

 nated from c, was established between b and c. A very slender ligament, 



