ON BUDDING IN POLYZOA. 523 



colony. Figs. 18 and 19 are consecutive sections of a similar 

 bud at a later stage, and illustrating the same point. Fig. 20 

 is a longitudinal section of a slightly later stage, showing the 

 oesophageal invagination inpinging upon the stomach. 



Eucratea chelata, L. — In old zooecia the bud is derived 

 from a small mass of cells, which is situated just below the 

 hinge of the operculum, and from the first is apparently in 

 equally intimate connection with both the endocyst and 

 strands of funicular tissue (PI. XXXVIII, fig. 21); subsequently 

 it occupies a central position just above the brown-body, and 

 then it commences to go through the characteristic develop- 

 ment. It is this stage which has, I imagine, deceived Joliet 

 into believing that the bud arises from the funiculus itself. 



In new zooecia the bud has a similar origin, only in this 

 case from the base of the zooecium. PI. XXXVIII, fig. 22, shows 

 the lophophore to be quite distinct from the digestive tract, 

 while the latter is closely connected with the funiculus. 



Alcyonidium gelatinosum, L. — A portion of the bud, at 

 all events, arises by invagination of the endocyst. PL XXXVIII, 

 fig. 23, clearly shows that both the epiblastic and the meso- 

 blastic layers of that tissue are equally implicated. 



Fig. 24 is a longitudinal section, corresponding to figs. 7, 20, 

 22, &c. 



I have, in fact, observed the distinctness of the lophophore 

 from the alimentary tract in the following forms: — Bugula 

 avicularia, B. flabellata, Flustra car base a, F. papy- 

 racea, F. securifrons, Eucratea chelata, Diachoris 

 magellanica, Alcyonidium gelatinosum, Vesicularia 

 spinosa. 



Larval Gemmation. 

 The phenomenon of budding is generally supposed to take 

 ])lace during the embryological history of a Polyzoan. The 

 following very brief summary of what is known on the subject 

 is abstracted from the late Prof. Balfour's 'Elements of Com- 

 parative Embryology,' vol. i. : the sentences within inverted 

 commas being transferred from that invaluable work. 



