56 THE VOYAGE OF H.M.S. CHALLENGER. 



The buds in the Tunieata are formed as outgrowths from the parent body, consisting, 

 probably in all cases, of part of the mantle covered by the ectoderm and enclosing a diver- 

 ticulum from some part of the alimentary canal. In this way portions of the hypoblast, 

 mesoblast, and epiblast of the parent are implicated, and these layers probably give rise 

 to the different systems of organs in the bud in much the same way as they do in the 

 embryo. 



Further details as to the process of gemmation are deferred till the second part of 

 this Report, which will treat of the Compound and Pelagic Tunieata, among which some 

 form .of budding and metagenesis is almost universal. 



