

FIG. 40. Obelia sp. A, portion of a colony with certain parts shown in longi- 

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

 oral aspect ; Bd. /, 2, buds ; bis. blastostyle ; coe. coenosarc ; ect. ectoderm ; 

 end. endoderm ; ent. enteric cavity ; g.th. gonotheca ; h.th. hydrotheca ; /. 

 lithocyst ; m.bd. medusa-bud ; mnb. manubrium ; insgl. mesogloea ; inth. mouth ; 

 p. perisarc ; P. /, 2,3, polypes ; rad. c. radial canal ; t. tentacle ; vl. velum. 



