SYSTEMATIC AND BIOLOGICAL ACCOUNT 87 



information at present available this is convenient, since there must remain doubt about the identity 

 of Moser's specimen. At the same time the number of siphonophore species is not large; and the 

 spinose condition is so unusual that there is some probability that Moser was really reporting (if not 

 accurately describing) the same species. 



Material. 



Dr Sears and I have been exchanging information for some time — a fortunate circumstance in days 

 when publication is so long delayed. As soon as Dr Sears informed me that she was publishing a note 

 on a new species N. spinosa I guessed that she was referring to the spinose Prayid I had for so long 

 been studying. I sent her a figure of a nectophore with obsolescent nectosac and she confirmed it. 

 But at the same time she asked if I had the nectophore as well as the ' bract ' ; and in her account, 

 which at the time was in the press, she again refers to the ' bract ', by which she means the bract of 

 the eudoxid. Describing its hydroecium she says that closely associated with it is a long tubular 

 somatocyst, and adds that on two of her specimens two thread-like branches are given off dorsally and 

 appear distally to have a 'globular connexion '. It is quite clear to me that the 'globular connexion ' 

 is the obsolescent nectosac, and that ' the two thread-like branches of the somatocyst ' are the dorsal 

 and ventral radial canals of the nectosac, so characteristically dissociated in N. thetis, instead of 

 arising with the lateral radial canals from a common pedicular canal as in most Prayids. 



In the very well-preserved specimen (PL V, fig. 1) from 'Discovery II ' Station 1 179, the opening 

 of the obsolescent nectosac is visible as well as the ring canal. 



In the three specimens to. which the gastrozooids are still attached the 'central organ' to which 

 I have referred (p. 81) in my notes on other Prayids, is visible. It is comparatively large in the 

 specimen from ' Discovery 1 1 ' Station 68 1 , and spreads down on each side of the base of the gastrozooid . 

 The tentilla of the same specimen are well preserved and show a peculiar spheroidal swelling at the 

 junction of pedicel and saccus. They have been examined only with a binocular microscope under 

 very bright illumination, because it is not advisable to dissect the only three complete specimens. 



Rosacea [? Q. & G.] Bigelow & Sears, 1937. 



After many years study of both living and preserved siphonophores and of the literature I have 

 come to the conclusion that we only know two species of the genus which Bigelow (1911^) and Bigelow 

 & Sears (1937) rightly or wrongly called Rosacea. The distinguishing features of these two species, 

 R. cymbiformis and R. plicata, is that the eudoxids have large gonophores and no special nectophore, 

 and a somatocyst canal system of the type figured by Bigelow (191 lb, pi. 2, fig. 4). A third alleged 



