ON THE LIFE-HISTOBY OF PEDICBLLINA. 165 



injury to the latter. I have been unable to show that calyces 

 ■which have thus left their stalks are able to become the starting- 

 points of fresh colonies. The specimens under observation have 

 invariably died after a day or two, even if kept in a tide-pool. 



Calyces formed at the scars produced in the manner above 

 indicated^ seem to me (from superficial examination of entire 

 specimens) to develop in exactly the same manner as those 

 produced at the true growing point. The occurrence of this 

 phenomenon is undoubtedly adverse to Hatschek's theory of 

 budding ; the whole of the stomach falls away with the calyx, 

 whilst the existence of a plug of cells filling up the diaphragm 

 appears to preclude the possibility of the migration of any 

 cells derived from the stomach to the proximal side of the 

 diaphragm Unless, indeed, it is assumed that some of the 

 " connective-tissue " cells of the stalks as well as of the stolon 

 are endodermic in nature, it must be concluded that none of 

 the cells of the bud are descendants of any of the cells belong- 

 ing to the embryonic hypoblast. 



With regard to the further history of the budding (whether 

 at the growing point or at the apex of an old stalk) I have very 

 little to say. The free end of the stolon (or stalk) before long 

 develops an ectodermic invagination (fig. 14) destined to give 

 rise to the lophophore and, according to my view, to the whole 

 of the alimentary canal of the bud. The latter is from the 

 first continuous with the lophophoral rudiment, and in other 

 sections of the series to which fig. 14 belongs, the stomach and 

 vestibular cavity are separated from one another by means of a 

 septum. The latter does not, however, cut off the whole of 

 the deepest part of the invagination, but, since it is not deve- 

 loped in the position of the oesophagus the vestibule and stomach 

 remain continuous with one another (as in fig. 14). By the 

 formation of a diaphragm and by other processes already 

 described by Hatschek, the bud attains its adult condition. 

 The continuation of the stolon is formed by a lateral outgrowth 

 from that region in the young bud which afterwards becomes 

 the base of its stalk, precisely as in fig. 13 with the exception of 

 the fact that the new growing point is formed long before the 



