Ixii INTRODUCTION. 



Joliet imagines that the deeply coloured buds, which I 

 supposed to originate from the germ-capsule, were really 

 buds tinted by the granules of a " brown body " which 

 had been thus dissolved in their interior. But this 

 explanation seems to me inadequate, as the appearance 

 referred to was presented by buds which had reached a 

 stage of development in which all traces of the substance 

 of the brown body must have vanished from the stomach. 



I will add a few further considerations that have been 

 urged or may be urged against the theory of Smitt. i. If 

 a branch of the polyzoon is treated with potash, all its 

 soft portions (the polypides, the endocyst, the endosarc) 

 are destroyed, but the " brown bodies " survive and are 

 commonly intact (Joliet). ii. The remains of the food 

 (Diatomacese, Foraminifera, &c.) and the hard portions of 

 the giz/ard (in the species possessed of this organ) are 

 sometimes recognizable in the " brown body " (Nitsche) . 

 iii. A very large number of brown bodies are often pre- 

 sent in the colony, which undergo little or no change, and 

 perish with the cell itself. These are usually found in 

 the older regions of the zoarium, which are destitute of 

 polypides ; they show no signs of reproductive power, 

 iv. Admittedly a very large number of the buds, by means 

 of which the poly pide is renewed, are formed at a greater 

 or less distance from the " brown body.""* These buds 

 have generally been regarded as the product of the endo- 



* I may here record an observation made on a specimen otBuguIa calathus 

 which I had dredged in full life and vigour. After keeping it for two or three 

 days the polypides over the lower two thirds (about) of a branch had perished, 

 and towards the base of each cell was a roundish dark reddish-brown body. 

 A little in advance of it in almost every zooecium was a polypide-bud, arising 

 (as it then seemed to me) from the endocyst-floor of the cell, consisting of 

 the crown of tentacles and a small sac suspended from it. Sometimes the 

 " brown body " was almost close to the bud, sometimes a little way from it ; 

 but in all cases a separation between the two was nere evident enough. 



