V 





MgMf 



Fig, 41. — 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 ; cce, ccenosarc ; eci, ectoderm; 

 end, endodernr ; ent, enteric cavity; gth, gonotheca (gonangium) : htk, hydro- 

 theca; /, hthocyst; m.bd, medusa-bud: mnb % manubrium; msgl % mesoglcea; 

 mth, mouth; f>, perisarc; P. 1, 2, 3, 4, polypes; rad. c, radial canal; t, 

 tentacle; vl, velum. 



93 



