36 DISCOVERY REPORTS 



The 'Discovery II' brought back a 'S.W.' specimen from Station 1738 in the South Indian Ocean 

 that measured: length 33 mm., breadth 18 mm., height of sail from apex of 'liver' 9 mm. This gives 

 a ratio of 54-5 % for breadth and length. 



The 'Discovery' collections also contain a series of twenty-seven 'N.W.' specimens from Station 

 2669 in the Western Mediterranean, as well as an interesting series of ' S.W.' specimens from Stations 

 WS 1057 and WS 1058 made in the South Atlantic between St Helena and Tristan da Cunha. The 

 ratio L/Br for these two groups of specimens is given in the table on p. 35. Only those specimens 

 fit for measurement are listed. 



Bigelow showed that the 'N.W.' condition of the sail was much more common in the Pacific 

 Velella lata than in the Atlantic V. velella. More data are needed on proportions and direction of sail. 



Distribution. In the Atlantic Velella extends from Cape Cod to at least 28 S. 



Feeding. The specimen from Station 1738 was 'brilliant indigo-blue' in colour when fresh; 'the 

 sail pale purple almost transparent '. Many of its gonozooids had been feeding on Crustacea, which 

 I have not attempted to examine or identify, and in many cases the mouths are still open. One 

 gonozooid had extended its mouth to a width of 2 mm. in an attempt to engulf a Calanoid copepod 

 (family Euchaetidae) which measured 2-5 mm. in length (excluding terminal setae). 



SIPHONOPHORA 



PHYSONECTAE 



At least eleven Physonect species are represented in these Indian Ocean collections, an increase of 

 50% on numbers last reported by Browne (1926). So far, very few Physonects at all have been 

 described and figured to the satisfaction of specialists, and though the systematic work on them is 

 always going on, it is necessary to send this report to press before it has been possible to complete it. 

 Quite apart from the morphological work entailed, the synonymy is very involved, as shown by the 

 classical example of Agalmopsis elegans Sars, 1846. Sars himself realized later that he had based his 

 name on two species. A discussion of the matter was published by Bigelow (191 1 ft). The two species 

 occur together commonly not only in Norwegian waters but off South-west Ireland and in the 

 'Celtic' Sea. Unfortunately each component, generally referred to as ' Agalma'' (trifid tentilla) 

 and ' Stephanomia' (filiform tentilla), has been renamed sarsii, the first by Kolliker (1853ft); ana 

 the second by Haeckel (1888 ft) as Cupalita sarsii. And finally Bigelow (191 1 ft) chose to use the name 

 elegans for the minor 'Agalma' component thinking that the major one was 'Stephanomia' bijuga. 

 My contribution to the discussion is to affirm, on the evidence of the nectophores (Sars, 1846, 

 Tab. 6, figs. 3-4) and of the palpon (Tab. 6, fig. 11), that fig. 1 of both of Sars's plates 5 and 6 repre- 

 sented at the time a new genus and species, a species later redescribed from the Gulf of Maine by 

 Agassiz (1865) and Fewkes (1888a) as Nanomia cara (see Text-fig. 19). The main concept that Sars 

 had in mind when describing his novelty was the species represented in twenty-four out of twenty-six 

 of his figures. Agalmopsis elegans obviously has priority as the name of the species to which they 

 belong, but Haeckel (1888ft, p. 234) chose to- restrict Agalmopsis to the other species. 



Two short visits to Villefranche have enabled me to study alive in the field six of eleven Physonects 

 found in the Indian Ocean and here reported upon, viz. Physophora hydrostatica, Stephanomia rubra, 

 S. bijuga, Agalma elegans, Athorybia rosacea Forskal (non Bigelow) and Cordagalma cordiformis, 

 together with a species of Forskalia ; and also to study alive the larvae of Physophora hydrostatica, 

 Stephanomia bijuga, S. rubra, Agalma elegans, and Forskalia sp. 



One of these species, Cordagalma cordiformis Totton, 1932, must be the smallest of all the Physonects. 

 At Villefranche I found loose nectophores frequently, and some minute, colourless colonies that 



