46 ZOOPHYTES. 



single stalk after each other, within 66 days. The complement of tenta- 

 cula crowning the first was accidentally overlooked. Probably it ex- 

 ceeded that of the second, which was regenerated with 16 ; while the 

 seventh head had only six. The meagreness of its aspect was extraordi- 

 nary. 



The hydra fig. 2, d, having fallen April 18. another with 18 tentacula 

 was generated on the 22d. Its successor, on May 13. had only 10 ; this 

 was replaced on the 30th ; it fell, and was succeeded on June 10. by one 

 having 8. But the next and last, which was scarcely visible, had only 



7.— PI. V. fig. 9. 



Thus, in the Tubularia larynoc, degeneration of the hydra is conco- 

 mitant on reproduction. 



In general this portion of the organization subsists five or six days. 

 The intervals of reproduction are quite indefinite ; sometimes, though very 

 seldom, a day or two intervenes between the disappearance of the old 

 hydra and the evolution of the new one ; sometimes from three to eight. 

 For the most part the stalk remains vacant for about five days. 



The finest regeneration commonly issues from the largest stalk. 



At first the new head is very minute : the heads of shorter stalks are 

 particularly so, and they are very pale : several have been scarcely percep- 

 tible, and the neck is extremely slender. Like the parts of the Tubularia 

 indivisa, both enlarge in time. The neck is prolonged also during sub- 

 sistence of its head, whence, by the accession of no more than the third 

 of a line at once, a specimen reproducing profusely, gains considerable 

 comparative altitude by the aggregate accessions. 



This, however, is ultimately productive of much inconvenience to the 

 observer, for the longer parts above and the shorter below, preserving no 

 regular or definite direction, they are respectively intercepted from the 

 eye, or interrupt the view of earlier reproductions. Thus, in the course of 

 June, the specimens figs. 2, 3, had become so intricate, by prolongations 

 and curvatures of the stalks ; and the hydrse had become so minute in re- 

 peated regeneration, that farther observations on them could not be satis- 

 factorily continued. 



The regenerative qualities of this product are very powerful, as it is 



