52 DISCOVERY REPORTS 



It is interesting to find such a close similarity between nectophores of Agalma elegans and 

 Stephanomia rubra because their tentilla are so very different. 



Bracts. In Mediterranean specimens the bracteal canal rises towards the dorsal (abaxial) surface 

 near the tip and forms an enlarged subterminal, elongated, cylindrical vessel provided with about 

 200 nematocysts (see Kolliker, 18536, Tab. iv). This subterminal section of the bracteal canal lies 

 under a short ridge. In the youngest bracts the subterminal section is bent at right-angles to the main 

 axis, and so is terminal (Text-fig. 14 B, C). 



In Indian Ocean collections, as indeed in those from the Atlantic, there are many small nectophores 

 and bracts that closely resemble those of the Mediterranean species S. rubra, and also some more 

 complete specimens that bear parts of both nectosome and siphosome. There are differences in shape 

 between many of these nectophores and some well-preserved ones of S. rubra that I was able to 

 anaesthetize at Villefranche. But in the present state of our knowledge it would be premature to 

 establish a new species for the Indian Ocean forms. 



For a long time it seemed possible to divide the Indian Ocean nectophores into two categories, one, 

 type '/', appearing to be somewhat more compressed or shortened in the abaxial-adaxial axis than 

 the other type 'e\ The appearance of the two types of nectophore as they lie flat on the bottom 

 of a watch-glass is quite different (cf. Text-figs. 16 A, B, E — type ' e\ and C, D, F — type '/'). But 

 if a different view-point is taken of the type '/' nectophore shown in Text-fig. 16C, we get the 

 appearance shown in Text-fig. 17B, which is that of type l e\ Although in the Mediterranean form 

 of S. rubra there is only a very small mouth-plate in the nectophore, if any at all, in these Indian Ocean 

 nectophores the mouth-plate is often conspicuous. Their canal system is indistinguishable from that 

 of S. rubra. Their bracts are very similar to those of the Mediterranean form but the bracteal canal does 

 not rise up abruptly towards the terminal ridge as it does in the Mediterranean form. Tentatively 

 I regard all these specimens as belonging to S. rubra. 



New Indian Ocean records. ' Manihine ' Aqaba Station 1 ; ten small but well-preserved nectophores. 



'Discovery II' Stations 1567, 1568, 1585, 1586, 1587, 1589, 2688, 2907 (Red Sea). 



Much more work must be done on the large amount of available Atlantic material before the 

 size-range of specimens and the variation in form of nectophores and bracts can be determined. It is 

 still uncertain whether there are other closely related species. The nectophores described and figured 

 in my (1932) Great Barrier Reef report as Agalma sp. indet. belong to Stephanomia rubra. 



Nanomia bijuga (Delle Chiaje), 1841. 



This species has been mentioned a good deal in the literature under many names : 



Physsophora bijuga Delle Chiaje, 1841. 

 Anthemodes canariensis Haeckel, 18696. 

 Halistemma pictum Metchnikoff, 1870. 

 H. tergestinum Claus, 1878. 

 Agalmopsis picta Fewkes, 1880. 

 Cupulita picta Chun, 1897a; Kawamura, 191 ib. 

 Stephanomia bijuga Bigelow, 191 ib (see synonymy). 



This species was not taken in the Indian Ocean either by 'Mabahiss' or by 'Manihine'. 

 'Discovery II' took only a very few, small nectophores as follows: 



St. 1 587 45°-° m - TYF B One nectophore. 



St. 1587 450-0 m. N 70 B Two small nectophores. 



St. 1589 600-0 m. N 70 B One small nectophore. 



