\ 



106 BULLETIN OF THE 



Summary. 



The following general scheme of the budding process iu Ectoprocta, 

 derived from my own and other recent studies, may be now drawn up. 

 The references are to pages of this paper. 



All Ectoprocta build stocks or corms. The individuals in these are 

 arranged in rows radiating from a centre, — the larva or statoblast, — 

 and are placed one in front of another (Figs. 2, 64% 65% 67, 71% etc.). 



New rows or branches are constantly being produced peripherally. 

 There is no dichotomy in the branching (page 86), but the ancestral or 

 median branch gives rise to one or moi'e lateral branches, which in turn 

 become median branches of their part of the stock. 



The body wall and poh'pides of the median branch, as well as the 

 Anlagen of lateral branches, arise from a pre-existing mass of embry- 

 onic tissue, the gemmiparous mass (pa^es 72-82). This may exist cen- 

 trally of the forming region, as in Phylactolcemata, or peripherally, as in 

 Gymnolaemata. 



The anal aspect of the polypide is turned towards the gemmiparous 

 mass (page 82). 



The outer layer of the body wall in the budding region is one 

 of rapidly assimilating and rapidly dividing tissue ; the inner layer of 

 the body wall becomes filled with food taken from the body cavity in 

 species in which the latter is early cut off by a partition (Paludicella, 

 Bowerbankia, Lcpralia f) ; it shows no tendency to do so in species witli 

 a cocnocoel (Phylactolajmata, Alcyonidium). 



The first impulse to the formation of the polypide is found in the 

 outer layer of the body wall (excepting when this is highly modified, as 

 in Cristatella), and many cells seem to be involved in its formation from 

 the beginning (pages 8, ^^^. 



This outer layer of the body wall is embryonic tissue, derived from the 

 tip of the stock (margin of the corm) as in Gymnolaemata, or from the 

 neck of pre-existing polypides, as in Phylactoltemata. It is the direct de- 

 scendant of the gemmiparous tissue of the larva, which in turn has been 

 derived from the region around the blastopore, — in Phylactolsemata cer- 

 tainly, in Gymnolfemata probably (pages 8, 11, 12, 69). 



The inner layer of the body wall is also embryonic in the budding 

 region, as indicated by the f;\ct that ova arise near the neck of the 

 polypide, in Phylactolaemata at least (page 68). 



The outer mural layer becomes the inner bud layer by invagination, 

 with or without the formation of a cavity. In the former case (man}^ 



