312 



fiE'rEiioMoui'iiy. 



trophy, Atrophy, &c., for malformations capable of 

 more rigid classification than those here alluded to. 



Formation of tubes. The production of ascidia or 

 pitchers from the cohesion of the margins of one or 

 more leaves has been already alluded to (see pp. 21,30), 

 but there is another class of cases in which the tubular 

 formation is due, not so much to the union of the 

 margins of a leaf as to the disproportionate growth of 



^ Pig. 166. Portion of the under surface of a cabbage-leaf, with horn- 

 like excrescences projecting from it. 



some portions as contrasted with others, whence arises 

 either a depressed cavity, as in the case of a leaf, or 



