• 



/ 



/ 





s 



- \ 



% * 



II 



* 







X 



■ of 



warc.tae 



y betid 

 aic; f 



HYDROZOA. 



31 



a while in this position, the fundus of the gastric 

 chamber contracts, and forces the globule through 



dilate at the 



moment 



The walls of the peduncle are thin and muscular. 

 Those of the gastric chamber are comparatively- 

 thick, while its cavity is wider than any other 

 part of the interior of the polypite. In addition 

 to the cilia, which clothe its endoderm, the surface 

 of this layer is often elevated into a number of 

 villi, or conical processes, which in Physalia attain 



Such villi, or ridge- 



length 



like enlargements which arise in their stead, have 



The coloured contents, occa- 



similar 



{fig 



are regarded by some anatomists as the most 

 rudimentary form of hepatic apparatus. In Ve- 

 lella and Porpita, more certain indications of a 

 liver are presented by a dark brownish mass, which 

 arises in connection with the digestive cavity of 

 the large central polypite (fig. 2 1, a). 



The nutrient matters elaborated within the 



polypites 



Here 



rm 



occurrence 



rt* observed within the long coenosarc of Tubularia 

 with 1 mdwuia. Currents have been seen to course up 



down the long stem of this Hyd 



*?1 9*™*}°^ appear to flow through distinct 



but these are nothing more than irregular cavities 

 produced by vacuolation of the endoderm (fig. 

 10, c d, and e). A circulation of albuminous 

 particles also takes place within the peculiar 



