HYDROZOA 



141 



Oph/^ 



Fig. 119. Examples of Hydrozoa. A and B, Calyptoblastea. C and D, Gym- 

 noblastea. A, Plumularia, small portion of a branch showing nematophores. 

 B, Sertularia, branch with opposite hydrothecae and gonotheca. C, Pennaria, 

 tip of branch. D, Eudendrium, showing migration of germ cells into gono- 

 phores. gph. gonophores; gth. gonotheca; hth. hydrotheca; nah. nemato- 

 phore ; ov-. migrating germ cells ; prs. end of perisarc ; ten.ab. aboral and ten.or. 

 oral tentacles. A, after AlLman; B and C, original; D, after Weismann. 



