4 o DISCOVERY REPORTS 



It seems, then, that in Athorybia the pneumatophore is never carried up by a growing zone above the 

 level of the young gastrozooids, and that an adult Athorybia is homologous in its general organization 

 with a larva of Nanomia bijuga turned on its side. It is homologous also with a young Physalia in 

 which the same turning has occurred, for the gastrozooids are in the same relative position to the 

 pneumatophore as they are in a larval Nanomia bijuga (Text-fig. 5 A, B). 



Bracts. The basal part, to which the muscle is attached, is flattened from side to side. The main 

 part of the bract is flattened dorso-ventrally. There are seven slight longitudinal ridges of nematocysts 

 on the dorsal surface. When the ectoderm is stripped off no ridges remain. Only the median row 

 reaches the proximal end. 



New Indian Ocean Records. 'Manihine' Aqaba Station 18, 1 example (juv.), bracts; Red Sea 

 Station 10, 1 bract. 



'Discovery II' Station 1589, 1 example (juv.), 1 bract. 



Other new records. 'Terra Nova' Station 57 (Tropical Atlantic, 13 May 1913), 1 example. 



' Discovery '. Four specimens were taken by dip-net on 1 6 October 1 925 at a position 29 56' 50" N . , 

 15 03' 10" W. and fixed in Schaudin. A note on the label by Professor A. C. Hardy reads 'small fish 

 [14 mm. long] was caught clasped by one of the Athorybia, but separated on being transferred from 

 net to fixative '. 



'Discovery' Stations 281, 282, 284, 299. 'Discovery II' Stations 689, 697, 698, 2069, 2648. 



Bermuda, Beebe Collection. Four specimens were recorded in a preliminary note under my name 

 in 1936 as Anthophysa formosa Fewkes. Beebe took another specimen number 29453, net 267. 



H.M.S. 'Rodney'; Kingstown, St Vincent, B.W.I. , 20 February 193 1 (Totton Coll.); 1 example. 



Melophysa Haeckel, 1888 

 Type species Rhizophysa melo Q. & G., 1827 



Eschscholtz (1829) included three species in his Athorybia. Of these, two — no doubt the same 

 species — Physsophora (sic) rosacea Forskal and Rhizophysa heliantha Quoy & Gaimard belong to one 

 genus Athorybia Eschscholtz, and the other Rhizophysa melo Q. & G. belongs to the quite distinct 

 genus which Haeckel (18880) named Melophysa. Bigelow (191 1 b) rejected this name Melophysa on the 

 grounds that Haeckel in his 'Challenger' Report (18886) referred to, but did not describe under this 

 generic name, a single specimen taken in the Strait of Gibraltar in 1867. It was lost before Haeckel 

 could draw it, but the form of its bracts was said to be similar to that in Athorybia melo, which Quoy 

 & Gaimard had observed in the Strait of Gibraltar forty years before and figured in their 'Astrolabe' 

 Atlas (pi. II, figs. 7-12). However, prior to publication of this 'Challenger' Report in 1888, Haeckel 

 had published in December 1887 and again in May 1888 in his System der Siphonophoren the new name 

 Melophysa, citing Rhizophysa melo Quoy & Gaimard as the only species. Perhaps this was overlooked 

 by Bigelow, but, bearing it in mind, we can hardly agree that Haeckel set up a new genus for 

 a problematical, undescribed and unfigured specimen that was soon lost. In fact I see no reason why 

 Haeckel's name, Melophysa should not be used for Quoy & Gaimard's species, Rhizophysa melo. 



The only good account of this species is by Bigelow (193 1) under the name Athorybia rosacea. 

 The probable origin of the confusion, both zoological and nomenclatural, is the fact that till figures 

 were published by Chun (18976) it was not realized that Rhizophysa melo had a distinct nectosome 

 with nectocalyces and that there was a characteristic difference between the heavy, ribbed bract of 

 melo and the light, striated bract of rosacea. 



