10-i 



EMBRYOLOGY 



(ScypMstoma) appears to lack the power of generating sexual 

 products, exhibiting only non-sexual reproduction, which 

 occurs in two modifications : (1) as budding (lateral budding 

 and formation of root-runners or stolons) (Fig. 50), by means 

 of which a scyphopolyp is always produced again — this 

 either separates from the parent and attaches itself independ- 

 ently, or may remain united with the parent, thus tem- 

 porarily producing small colonies (scyphopolyp stocks) — (2) 



""^P^ ' 



7 8 9 12 



Fig. 51.— Cycle of development of .4i(i-elirt auriia (from Katsckkk's Lehrhuch). 

 1, planula ; 2, attached larva; 3, j'oung Scyphistoma with four tentacular buds; 4, 

 Scyphi-toma with stdlonic growth ; 5, beginning of the strobilization, indicated by 

 a circular furrow; 6, 8, 9, 10, various strobila; polydisra^; 7, Scyphistoma from 

 above ; 11, Ephyra from the side ; 12, Ephyra from below. 



as strobilization, in reality a transverse division with subse- 

 quent regeneration. By means of transverse constrictions 

 the scyphopolyp (Fig. 51, e) separates into superposed dis- 

 coid parts (strohila stage, Fig. 51, 5 — 10), each one of which, 

 by the production of marginal lobes and corresponding 

 internal metamorphoses, is changed into a young medusa, 

 which at first shows the characiteristic form of the E})hyra 

 stage (Fig. 51, n, 12), and is not converted into the permanent 



