SYSTEMATIC AND BIOLOGICAL ACCOUNT 157 



of the anterior one. This comb or ' Leiste ' is the homologue of the comb or ' Leiste ' in Abyla spp. The 

 hydroecium of the posterior nectophore has been displaced to the left side in the proximal half. 

 I observed at Villefranche that the tip of the tentacle consists of a sinker in the form of a disc, around 

 the edge of which are from 13 to 16 nematocysts. A similar sinker occurs at the tip of the tentacle of 

 Rosacea cymbiformis. 



Cmb- - 



To.L- 



Tovl. A 



C.radd 



radlat 



~i~~C ' radv 



- - Whydr 



Whydr 



Text-fig. 83. Abylopsis tetragona, posterior nectophore, to show how the left ventral hydroecial fold is held rigidly in place 

 by the right. A, latero-ventral view, x 5 ; B, a section just above the locking tooth of the right wing, x 8-8 ; C, apical view, x 8-8. 



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20-3 



