PROPAGATION OF TUBULARIA. 103 



cumstance of the wound closing ; but from the mo- 

 ment that the rising internal bud reaches the vacant 

 extremity of its integument, the neck, or that portion 

 sustaining this young Hydra, visibly lengthens until 

 further prolongation is arrested by the separation and 

 fall of the regenerated parts. The wound cicatrizes 

 again. If the process of reproduction is repeated by 

 another polyp rising within, to issue in its turn from 

 the summit, a new prolongation ensues also, and so 

 on with a third, fourth, or more. Thus are formed as 

 many nodes or articulations of the stem. But the 

 irregular duration of the successive Hydrse or heads 

 produces an irregularity in the accessions to the length 

 of the stalk. One shoot extending six or eight lines 

 may be followed by another only two or three, and 

 the prolongations seem scarcely sensible when the 

 head nourishes merely to decay. Let it, however, be 

 remembered, that the prolongation of the neck, which 

 takes place at these intervals, is the sole mode of ex- 

 tension in the stem of the zoophyte. 



The renovated shoot is at first flexible, especially 

 towards the head, but in time greater rigidity ensues, 

 and the colour fades. In full-grown and fertile spe- 

 cimens of Tubularia, several florid clusters, resembling 

 minute bunches of grapes, with three, seven, twelve or 

 more berries in each, weigh down the most luxuriant 

 heads. These constitute the ovarium, composed of 

 so many capsules or cysts, each, in an advanced stage, 

 containing a single embryo. The greatest disparity 

 of size and number prevails among the cysts and the 

 clusters, nor are they of uniform figure. Each cluster 

 is suspended by a hollow stalk from the lower part of 



