Fig. 78. Obelia. A, portion of a colony with certain parts shown in longitudinal 

 section ; B. medusa ; C, the same with reversed umbrella ; D, the same, oral 

 aspect ; Bd. /, 2, buds ; bis. blastostyle ; ca>. ccenosarc ; ect. ectoderm ; end. 

 endoderm ; ent. enteric cavity ; g.th. gonotheca ; h.t/i hydrotheca ; /. lithocyst ; 

 in.bd. medusa-bud ; tnnb. manubrium ; insgl. mesogloea ; inth. mouth ; p. peri- 

 sarc ; P. /, ,?, j, polypes; rod. c. radial canal; t. tentacle; vl. velum. (From 

 Parker and Haswell's Zoology, reduced.) 



