ON BUDDING IN POLYZOA. 519 



upon the caecal stomach, the two organs coalesce and their 

 lumens become continuous by wall-absorption. Tliis diver- 

 ticulum is the oesophagus, and the polypide has now the 

 characteristic form of the adult. 



The woodcut (fig. 1) indicates the relation of the developing 

 bud to the zooecium far better than a verbal description can do. 



Very shortly after this, owing partly to absolute increase in 

 size and also to the elongation of the tentacular sheath, the 

 polypide has come into contact with the brown body, which, as 

 was before mentioned, lies near to the bottom of the zooecium 

 (PI. XXXVII, fig. 8). The walls of the stomach, or more 

 strictly, that portion of the stomach which forms the gastric 

 caecum, grow round and envelop the brown body, so that the 

 brown body passes as a whole into the alimentary tract of 

 the young Flustra, which now has the form depicted in 

 PI. XXXVII, fig. 9. 



The brown body immediately commences to undergo disin- 

 tegration, and, previously to passing into the intestine, the 

 remains are whirled round and round within the globular pyloric 

 portion of the stomach by the action of the minute cilia with 

 which the latter is clothed (PI. XXXVII, figs. 10 and 11). 

 Ultimately all trace of the brown body, as such, is lost save a 

 small quantity of faecal matter in the intestine, and by this time 

 the gastric glands become very apparent (PI. XXXVIII, fig. 12). 



The reason why these buds, at this stage, appear of a dif- 

 ferent colour from the ordinary marginal buds of the colony, 

 as was first noticed by Hincks and animadverted upon by 

 Joliet (17) (still later, see Hincks (1) pp. Ivii, Ixii), is pro- 

 bably owing to the digestion of the brown body with the 

 concurrent development of digestive glands, the other buds 

 gaining the whole of their nutriment directly from the parent 

 tissues, and thus not requiring a distinct digestive apparatus. 



Annulations of the stomach at this stage indicate the exist- 

 ence of circular muscles, the walls of the pylorus become mus- 

 cular and much thicker, and, as before mentioned, its lumen is 

 ciliated, the caecum is a wide pouch lined with secretory cells. 

 The intestine is swollen, while the rectum is a short very 



