TIMA FORMOSA L. AGASSIZ 



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bit 



ins?. .. 



FIG. 6. Schematic section through a hydromedusa in the region of the 

 velum after Delage and Herouard (Zoologie Concrete), cnlc, circular canal; 

 cntt, tentacular canal; msg, mesogloea; cnr, radial canal; mslso, muscular 

 fibres of subumbrella; mclvt, muscular fibres of velum; brt, nettle cell battery; 

 ne, external nervous ring; ni, internal nervous ring. 



eight adradial tentacles. Of the remaining sixteen tentacles, 

 eight are per-adradial (halfway between a per-radial and adra- 

 dial tentacle) and eight interadradial (halfway between an in- 

 terradial and an adradial tentacle). 



Body layers. The body of the medusa is composed of 



