324 Natural History of British Zoophytes, 



kind to be altered by it, and hence unnoticeable, or because the dura- 

 tion of the whole is too fugitive to permit the law to produce a vi- 

 sible effect. 



There are facts which appear to prove that the life of the indivi- 

 dual polypes is even more transitory than their own cells ; that like 

 a blossom they bud and blow and fall off or are absorbed, when an- 

 other sprouts up from the medullary pulp to occupy the very cell of 

 its predecessor, and in its turn to give way and be replaced by an- 

 other. When speaking- of flexible corallines Lamouroux says, " Some 

 there are that are entirely covered with polypi through the summer 

 and autumn, but they perish with the cold of winter: no sooner, 

 however, has the sun resumed his revivifying influence than new 

 animals are developed, and fresh branches are produced upon the old 

 ones." * Of the Tubularia indivisa, Sir John G. Dalyell tells us that 

 " the head is deciduous, falling in general soon after recovery from 

 the sea. It is regenerated at intervals of from ten days to several 

 weeks, but with the number of external organs successively diminish- 

 ing, though the stem is always elongated. It seems to rise within 

 this tubular stem from below, and to be dependent on the presence 

 of the internal tenacious matter with which the tube is occupied. 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."f The observations of Mr Harvey ou the 

 same, or a very nearly allied, species of zoophyte confirm the expe- 

 riments of Sir J. G. Dalyell, so far as these have reference to the 

 deciduousness of the polypes and their regeneration ; J and it seems 



* Corall. Flex. p. xvi. 



f Edin. New Phil, Journ. xvii. p. 413. 



% " 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 

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

 away, but 1 happened to be under the necessity of quitting home for two days, 

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

 top of every tube -. 1 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 

 discover 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 ani- 

 mal." — Proceed. Zool. kSoc. No. 41, p. 55. 



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