180 



Proceedings of the Royal Irish Academy. 



flaccid. There are two sorts of tentacles : some occur near the margin of the 

 disc, and are arranged in alternating cycles, decreasing in size from within 

 outwards, though there may be irregularities about size ; others occur on 

 the disc itself, between the peripheral series and the moutli, and these too 

 are arranged in cycles, but are placed on the same radii as some of the 



Kio. 1. 

 Number* indicntc lentacle-cydes. 



marginal set. In the large animal the maipnal tentacles are 6 + 15+21 t 

 26 = 68 in number ; in the small one they are 6 + 14 + 20 + 20 = 60, and 

 here one of the secondary tentacles is double. Tlie disc-tentacles occur on 

 radii l>elongint,' to the o inner cycles of marginal tentacles ; they run 5 + 15 

 + 11 = 31 in the large si)ecimcn (one of the directive radii having no tentacle 

 but its marginal one), and 6 + 14 * I in the smaller. In each case the 3rd 



