BUDDING. 



47 



the parent-polypide, as the direct descendant of the latter (Fig. 23). 

 Only later does it shift further from the parent-polypide, newly- 

 formed parts of the zooecial wall being interposed between them. 

 This latter is the type of budding in which the polypide forms first. 



The zooecium of the bud is not always a direct outgrowth of the parent- 

 zooecium, for budding may be brought about by special basal extensions (stolons) 

 as, for instance, in the Cyclostomatous Bryozoa (Ostroumoff, No. 25), and in 

 some of the Ctenostomata (the group of the Stolonifera). 



,.ec 



Fig. 23. — A and B, two ontogenetic stages of the lateral buds of Crista'ella. C, development 

 of the median buds of the same form (after Braem). a, developing polypide ; b, the bud 

 developing on it ; at, atrium ; d, rudiment of the intestine ; ec, ectoderm ; I, rudiment of the 

 lophophore. 



It appears that in all Bryozoa budding takes place only at definite parts of 

 the parent in which the original capacity for regeneration has been retained. 

 In the Phylactolaemata, in which asexual reproduction according to the type in 

 which the polypide precedes the zooecium is retained, the rise of a new polypide < 

 rudiment is, as first shown by Hatschek, and more recently by Braem and 

 Davenport, always connected with an already developing polypide-rudiment 

 (Fig. 23). While the parent-polypide, which was originally a bilaminar 

 invagination of the body- wall, develops in the way described above (Fig. 23 A, a), 

 there is often found at the neck of this invagination, on its oral side, an 

 outgrowth ; this is the rudiment of the daughter-bud (6). As the two rudiments 



