80 DISCOVERY REPORTS 



Seven other captures, all made by ' Discovery ' in the Tropical and South Atlantic are as follows : 



P. = polygastric. 



e. = eudoxid stage. 



Recent 'Scotia' captures are: 



P. = polygastric. 



E. = eudoxid stage. 



The characteristic relationship of Leloup's 'formation speciaW (Bigelow's 'bilobed vesicle') with 

 the bracteal and pedicular canals of the eudoxid is complex. I give two new figures which show that 

 in the particular specimen figured, the pedicular canal of the special nectophore of the eudoxid arises 

 from the ventral side of the central organ, and that all the ' canals ' at this point do not meet at a point 

 (Text- fig. 36 B). 



The 'central organ', which lies in the hydroecium, is substantially the same as figured in Leloup's 

 diagram (1933, pi. 1, fig. 13), and in Bigelow & Sears (1937, fig. 5). I believe that it serves as a food 

 reservoir. Its upper wall forms a pouch, which spreads over on to the base of the gastrozooid. In 

 a recently captured specimen ('Scotia' 1951, haul 363) the bilobed vesicle figured by Bigelow can be 

 seen clearly. There is a ring of deeply staining tissue (? Bigelow's pedicular plate) between the 

 central organ and the basal bulb (basigaster) of the gastrozooid which unites everything together, and 

 from which the gonophores spring. The special nectophore is attached by a long semicircular adhesion 

 to the junction of what I will call the semicircular bracteal canal (Text-fig. 36, C.br.s.) and the central 

 organ. But the cavity of the bracteal canal system is isolated from that of the stem in the fully formed 

 eudoxids of Prayids. In young stages of Rosacea cymbiformis I have seen a canal connecting the bracteal 

 canal system to the stem, but later that disappears. The pedicular canal of the special nectophore of 

 Nectopyramis thetis does not arise, as it can appear to do, from the semicircular bracteal canal, but from 

 the central organ itself. This is what might be expected since I have discovered that in Rosacea plicata 

 the central organ of the eudoxid represents a development of the remains of the stem. The central 

 organ of Nectopyramis thetis varies in its state of development. Where it appears triangular (Text- 

 fig. 3 5 A) I think it is ageing, and what looks like a descending canal is only a constricted part of the 



