90 ZOOPHYTA HYDROIUA. 



cupied. A head springs from the remaining stem, cut over very 

 near the root ; and a redundance of heads may be obtained from 

 artificial sections, apparently beyond the ordinary provisions of 

 nature. Thus twenty-two heads were produced through the 

 course of 550 days, from three sections of a single stem."* The 

 observations of Mr Harvey on the same, or a very nearly allied, 

 species of zoophyte confirm the experiments of Sir J. G. Dal- 

 yell, so far as these have i-eference to the deciduousness of the 

 polypes and their regeneration ; -f- and it seems to me not alto- 

 gether unwarrantable to infer a like temporary existence and re- 

 vival in those of the Sertulariadse from a reflection on the ex- 

 periments of Mr Lister, — incomplete certainly, but which prove 

 that under certain circamstances their polypes disappear by a pro- 

 cess of internal absorption,;]: and under convenient circumstances 

 would probably have been renovated, as I have witnessed this re- 

 sult in similar experiments. On Saturday, May 28th 1837, a spe- 

 cimen of Campanularia gelatinosa was procured from the shore, 

 and after having ascertained that the polypes were active and entire, 

 it was placed in a saucer of sea-water. Here it remained undis- 

 turbed until Monday afternoon, when all the polypes had disap- 

 peared. Some cells were empty or nearly so, others were half-fil- 

 led with the wasted body of the polype, which had lost, however, 

 every vestige of the tentacula. The water had become putrid, and 

 the specimen was therefore removed to another vessel with pure 

 water, and again set aside. On examining it on the Thursday, 



* Edin. New Phil. Joum. xvii. p. 415. 



t " The most singular circumstance attending the growth of this animal, and 

 which I discovered entirely by accident, remains to be mentioned. After I had 

 kept the clusters in a large bowl for two days, I observed the animals to droop 

 and look unhealthy. On the third day the heads were all thrown off, and lying 

 on the bottom of the vessel ; all the pink colouring matter was deposited in the 

 form of a cloud, and when it had stood quietly for two days, it became a very 

 line powder. Thinking that the tubes were dead I was going to throw them 

 iiway, but I happened to be under the necessity of quitting home for two days, 

 and on my return 1 found a thin transparent film being protruded from the top 

 of every tube : I then changed the water every day, and in three days time every 

 tube had a small body reproduced upon it. The only difference that I can dis- 

 cover in the structure of the young from the old heads, consists in the new ones 

 wanting the small red papillce, and in the absence of all colour in the animal." 

 — Proceed. Zool. Soc. No. 41, p. 55. 



I Phil. Trans. 1834, p. 374, 376. 



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