SYSTEMATIC AND BIOLOGICAL ACCOUNT 151 



the comb of the right ventral wing, and the shape of the ventral teeth is the same. It is true that in 

 a young posterior nectophore of one of the 'Challenger' specimens of A. carina which is only just 

 emerging from the hydroecium of the anterior nectophore, the ventral teeth are relatively longer, 

 narrower and more spiny, but this difference is probably a matter of age and growth. 



In order satisfactorily to delimit species of the A. trigona group, much statistical analysis will have 

 to be made on large samples of swarms. 



Dr Sears has already published a description of another new species of this group. 



Abyla tottoni Sears, 1953. (Plate IX.) 



Dr Sears recorded the capture in 1930 of 27 complete colonies, 30 anterior and 19 posterior necto- 

 phores of Abyla tottoni at three ' Dana ' stations in the subtropical South Atlantic, as well as one anterior 

 nectophore from between ' Timor and New Guinea '. 



'Discovery II' took 12 complete colonies, five anterior and six posterior nectophores and three 

 eudoxids of this species in 1933 at Station 11 78 close to one of these 'Dana' stations; and a young 

 specimen (post. nect. 15 mm. 1.) some 1500 miles further west in the same region at Station 686. 



The whole margin of the larger ventral wing may be serrated. There may be from 12 to 13 teeth 

 on its inner basal margin, and from 1 1 to 13 teeth on the basal margin of the smaller wing, the ventral 

 corner of which, between comb and base, is more rounded than shown by Dr Sears (fig. 15 B). The 

 number of comb teeth may be as large as 12. But it is difficult to count comb teeth at the apical end, 

 and to agree on the number when there are smaller intermediate teeth, or the final apical one is not 

 well marked. 



This appears to be a distinguishable species, and I had already marked it as a new one. 



Abyla haeckeli Lens and van Riemsdijk, 1908. 



Until Dr Sears published her revision of the Abylinae I had assumed that all anterior nectophores 

 of Abyla, in which the apico-ventral facet was subdivided by a transverse ridge, belonged to the 

 species haeckeli. Whilst this report was in the press I re-examined my figured material. All the anterior 

 nectophores from ' Discovery II ' E. African stations are relatively small, and have the type of ventral 

 facet described and figured by Dr Sears for haeckeli. All the specimens from ' Discovery II ' Atlantic 

 stations are relatively large, and have a ventral facet of the type described and figured by Dr Sears 

 for ingeborgae. I am hoping that these two forms will prove to be quite distinct species, though 

 Browne's specimens seem to be intermediate. 



Dr Sears (1953) has published a figure of a young posterior nectophore for the first time. She 

 appears to have examined 10 colonies, 553 anterior nectophores and 51 posterior nectophores from 

 38 'Dana' hauls. This should be a good sample, and it is hoped that some one will have time to 

 establish the range of specific variation. 



I have re-examined the three anterior nectophores described by Browne (1926). Two of them 

 measure 6-i mm. in length, the third measures 6-9 mm. One of these, specimen 'A' is 4-6 mm. wide, 

 but two are rather squashed, and their width cannot be measured. Specimen 'A' is in good condition 

 and the horizontal ridge in side view is only slightly above the middle of the somatocyst (i/i-i). 

 Dr Sears's critical proportions of the pentagonal ventral facet, namely width-between-middle-corners/ 

 length-from-middle-corners-to-tip are as follows: 1/0-65, l l°'75> 1/0-82. The proportions of the facet 

 figured by Dr Sears (fig. 13 D, E) for A. haeckeli were 1/0-57 an d f° r A. ingeborgae i/i-i. On the basis 

 of these last two characters, as well as that of the ventral view, Browne's specimens are intermediate 

 between Dr Sears's figs. 13 D and E. The total size, the relative size of the apico-ventral facet, and the 

 size and position of the lateral projections lead me to conclude that they belong to A. haeckeli. 



