534 ALFRED C. HADDON. 



zooecia likewise very frequently lose their polyps by decay, 

 but long before the polyps have lost their characteristic form, 

 and have become brown-bodies, the endocyst of the upper end 

 of this zooecium begins to form a new polyp by budding in- 

 wardly. In the same zocecium we very frequently find a 

 decaying polyp, which very distinctly shows its original 

 nature, together with a new young bud, which does not differ 

 in the least from the polyp-buds in the zooecium-buds at the 

 edge of the colony. Here, also, the new polyp is formed, just 

 as the old one, by the budding of the endocyst of the zoa3cium 

 inwardly (p. 466). By "polyp" Nitsche, of course, refers to 

 the alimentary tract, as he accepts the dual nature of the 

 zooecium and its contained digestive apparatus. 



Salensky (9) states (p. 55) that the internal tissue of the 

 two-layered bud is derived from the external epithelium of the 

 endocyst of the parent, and the outer from the internal layer. 

 Here again the lophophore and digestive tract are epiblastic 

 structures, while the mesoblast of the bud is derived from the 

 mesoblast of the parent. 



Joliet (17) refers all the buds to his "endosarc." Under 

 the term ' endosarc ' Joliet includes " all the formations which 

 one calls under the names of colonial nervous system, funiculus, 

 fusiform layer of the endocyst." " It is this which constitutes 

 the muscular tunic of the fresh-water Bryozoa, the paren- 

 chyma of the stems of the stolons of the Pedicellinse, and of 

 the feet of Loxosoma." 



He says that it is a " provisional name,^' " whicli I sball be 

 quite disposed to change for another more general term as soon 

 as I shall have seen, or someone has shown me, its homologue 

 with the ectoderm or the endoderm of allied animals or of the 

 embryo." Surely neither alternative is necessary ! It will be 

 seen from what follows that I do not regard the funiculus as a 

 simple structure, nor the bud as entirely derived from the funi- 

 culus, therefore I cannot class all the contents of a zooecium, 

 save the outer layer of the endocyst, as being formed from an 

 homologous tissue. The tissue, as he describes it, answers in 

 position, structure, and generally in function, to the mesoblast 



