CNIDARIA 



55 



as slight elevations, in the interior of whicli are to be recog- 

 nized coi-ds of entoderm cells continuous with the wall of the 

 gastral cavity (Fig. 21 B). This tentacle-bearing stage, 



Fig. 21. — Two stages in the development of Liriope mucronaia (after Metschni- 

 KOPr), diagrammatic. A, a larva of the fifth day ; B, a seven-day larva in optical 

 section ; ec, ectoderm; en, entoderm; o, mouth-opening ; v, fundament of the 

 velum ; t, that of the primary perradial tentacle. 



which does not yet reveal the peculiarities of the medusa, 

 may well be regarded as a modified actinula-stage. 



