GENERAL ZOOLOGY 



Fig. 10.8. Asexual reproduction by budding; in 



I'elmatnhydra oliaaclis. (Redrawn from L. H. Hvman, 



1930, Transactions of the American Microscopical Society, 

 vol. 49.) 



developed powers of asexual reproduction, hydras and the coelenterates in 

 general have a marked capacity for regeneration. When a hydra is cut 

 transversely into two pieces, a new basal part appears on the piece having 

 tentacles, and new tentacles, mouth, hypostome, and zone of proliferation 

 develop at the distal end of the basal piece. In a few days two complete 

 hydras will have been formed and will have gradually assumed the normal 

 proportions. As might be expected from knowledge of its peculiar cellular 

 constitution, the extreme basal region has verv limited powers of regeneration. 

 In more distal regions, however, regeneration and subsequent growth of new 

 individuals occur even when the animal is cut into several small pieces. 



300 



