332 



POLYZOA INFLINDIBFLATA. 



parent law, that any structure which prevails in one class will be 

 produced in a lesser degree in some others — that since so many 

 plants are compound, so would some animals be thus constructed. 

 It requires, however, a greater effort of reason to view a bud as an 

 individual, than a polypus furnished with a mouth and intestines ; 

 and therefore the union does not appear so strange. 



" Our conception of a compound animal, where in some respects 

 the individuality of each is not completed, may be aided, by reflect- 

 ing on the production of two distinct creatures by bisecting one with 

 a knife, or where nature herself performs the task. We may con- 

 sider the polypi in a zoophyte, or the buds in a tree, as cases where 

 the division of the individual has not been completely effected. In 

 this kind of generation, the individuals seem produced only with re- 

 lation to the present time ; their numbers are multiplied, but their 

 life is not extended beyond a fixed period. By the other, and more 

 artificial kind, through intermediate steps or ovules, the relation is 

 kept up through successive ages. By the latter method many pecu- 

 liarities, which are transmitted by the former, are obliterated, and 

 the character of the species is limited ; while on the other hand, cer- 

 tain peculiarities (doubtless adaptations) become hereditary and form 

 races. We may fancy that in these two circumstances we see a step 

 towards the final cause of the shortness of life." — Voyages of Adven- 

 ture and Beagle, vol. iii. p. 259-62. 



Fig. 65. 



These " Bird's-head processes " have recently been described with 

 great care by Van Beneden and Professor John Beid.* Of British 

 Zoophytes they have been found on Cellularia ciliata, avicularia, 

 plumosa, scruposa and rep tans, on Flustra avicularis and murrayana, 

 on Eetepora cellulosa, and, as Lieut. Thomas writes me, on Lepralia 

 ciliata and coccinea. They are not present on every specimen of any 



* Nordniann and Krohn have also described tliem, but the works of these authors 

 are not accessible to me. 



