INTRODUCTION. Ivii 



Ehlers records an observation wliicli would seem to show 

 thatj in Alcyonidium at least, the tentacles are separated 

 from the alimentary canal during the progress of the 

 histolysis'^. 



In any case the "brown body " is derived from the poly- 

 pide, mid is the result of its decline. 



ii. As to its nature and destination, is it capable of 

 giving origin to a new polypide ? The simple ground on 

 which Prof. Smitt and myself have taken the affirmative 

 side is direct observation. In numerous cases the Swe- 

 dish zoologist has traced the formation of a 

 bud on the '' brown body/" and, as it seemed 'S- ^^' • 



to him, out of its very substance f. My own 

 observations have been to the same effect. 

 Repeatedly I have seen gemmation taking 

 place in the closest proximity to the surface 

 of the " brown body ;" and the bud, as I was fully per- 

 suaded at the time, was continuous with it and a growth 

 out of it. One thing, at least, we may claim to have 

 established and brought prominently into view, the fact 

 that there is so commonly the closest association between 

 the polypide-bud and the '' brown body " in the cell of 

 the Polyzoon. 



Another point my observations seemed to me to have 

 established — that the polypides developed from the (so- 

 called) germ-capsule differ in appearance during their 

 early stages from those which are found in the young 

 marginal cells of the colony, and from other buds which 

 occur in the adult zooecia. The latter are destitute 



* "HypopTwrella expansa, ein Beitvag," &c., Abhaudl. konigl. Gesellsch. 

 d. Wissensch. zii Gottingen, vol. xxi. (1876)p. 122. 



t Op. cit. pp. 23-29, pi. V. figs. 5, 17-19. See Woodcut, fig. xxii. 



