ON BUDDING IN POLTZOA. 525 



" Adopting the hypothesis already suggested in the case of 

 the Entoprocta, the metamorphosis just described would seem 

 to be a case of budding accompanied by the destrucion of the 

 original larva/^ 



" This view of the nature of the post-embryonic metamor- 

 phosis is apparently that of Claparede and Salensky, and is 

 supported by Claparede's statement (see below, p. 538) that the 

 formation of the first polype 'resembles to a hair' that of the 

 subsequent buds/' p. ^349. 



Dr. W. Kepiachoff (14) in his study of the development of 

 Tendra zostericola, says that he cannot with certainty 

 say how the inner epithelium of the middle and hind gut arises, 

 but his figures clearly show that this tissue is intimately con- 

 nected with the " brown-mass/' Several figures in his 

 plate viii, indicate the occurrence of an epiblastic involution 

 at the pole of the embryo, opposite to that where the blastopore 

 has closed up. This invagination will form the external layer 

 of the tentacular sheath, the outer epithelium of the tentacles 

 and the CESophagus of the primary zooid ; it is in fact the 

 stomodBeum. The pedicle of invagination of the archenteron 

 is absorbed, the latter being the rounded body, which he calls 

 the " brown-mass." From one end of this a U-shaped promi- 

 nence is produced, which is apparently hollow from the very 

 commencement of its formation, the remainder of the mass 

 being solid : this is the future intestine. The outer cells of the 

 " brown mass " differentiate into the inner epithelium of the 

 stomach, which soon acquires a free communciation with the 

 exterior through the asophagus. The central residual portion 

 of the " brown-mass" is digested within the stomach like any 

 other food-yolk. The " brown-mass " is surrounded by a deli- 

 cate membrane, the splanchnopleure. To render the above 

 account more clear, I reproduce his fig. 7, woodcut No. 2, 

 which compare with woodcut No. 1. 



It is clear, if the above be a correct interpretation, that the 

 initial individual of a colony, in this species at all events, passes 

 through a development which is normal in all its essentials, nor 

 does there appear to be any histolysis of the primal y larva. 



