NARCOMEDUSAE 



65 



Genus Pegantha Haeckel 



The diagnosis of this genus given by Bigelow (1909, p. 83) is as follows : ' Solmaridae with canal system 

 and otoporpae; the gonads forming diverticula of the margin of the oral gastric wall. 8-32 tentacles'. 

 Apart from the number of tentacles, which may amount to 40, I agree with this definition. It was 

 slightly altered by Bigelow (1918, p. 394): 'Solmaridae with peripheral canal-system (at least in one 

 generation), and with otoporpae; with gonads localized at the edge of the stomach, as numerous as, and 

 in the radii of, the marginal lappets.' In some cases, however, the interradial sexual pockets are 

 combined with an annular gonad, and in young specimens no interradial pockets are developed. 



The genus Pegantha, as here defined, conforms with the entire family Peganthidae Haeckel (1879, 

 p. 323): ' Narcomedusen ohne Radial-Canale und ohne Magentaschen in der Subumbrella; aber mit 

 einem Festoncanal (oder einem Ringkanal, der einen Kranz von getrennten Lappencaniilen bildet); 

 mit Otoporpen oder Horspangen an der Basis der Horkolbchen.' The family was divided into four 

 genera, exclusively according to the structure of the gonads: Pegasia Peron & Lesueur 1809, Polyxenia 

 Eschscholtz 1829, Polycolpa Haeckel 1879, and Pegantha Haeckel 1879. There is no reason whatever 

 to keep these genera apart, and the question then arises, which generic name should be preferred. 

 Bigelow (1940, pp. 303-4) has discussed this; he retained the name Pegantha, but with the addition: 

 ' Should it prove, in the future, that the gonads must be discarded here, as a generic character, the 

 name Pegasia (or if not Pegasia, then Polyxenia) will have priority.' It seems to me, however, that 

 Mayer (1910, p. 441) has settled the question by his remark: 'The names Pegasia and Polyxetiia 

 are older than Pegantha, but they are so hopelessly confused through vague and inaccurate description 

 that I believe it will be necessary to allow them to lapse into oblivion.' It also seems to me that an 

 identification of Haeckel's three species of Pericolpa remains doubtful; none of them have been 

 found again, and though a full description of the only specimen of P. forskali is given in the Chal- 

 lenger Report (Haeckel 1881) with several figures, an examination of fresh material is necessary to 

 prove the correctness of his observations. On the other hand, Haeckel's genus Pegantha contains 

 a number of well-described species, and I prefer, therefore, to retain the name Pegantha. 



Haeckel's 'Peganthidae' comprised 16 species. Within each of his four 'genera' the species are 

 characterized by : external shape of the umbrella, number and shape (outline) of the marginal lappets, 

 shape of the gonads, number of marginal sensory clubs and otoporpae; but no attention is paid to 

 the length of the otoporpae, and the conformation and width of the peripheral canals are entirely 

 disregarded. 



From time to time no less than 29 species have been referred to Pegatitha. A provisional revision 

 was attempted by Bigelow (1918, pp. 394 AF.), but, as pointed out by this author himself, larger 

 series of specimens are required to obtain reliable results. The present collection contains a consider- 

 able number of specimens, but a satisfactory preservation of these delicate medusae requires very 

 careful handling of each specimen. As a matter of fact, I do not think a successful revision of this 

 and other groups of Narcomedusae will be possible, until a specialist gets an opportunity to study 

 them immediately after they are brought up from the sea and picked out from the mass of crustaceans 

 and pteropods and other animals contained in the plankton samples. The following revision of the 

 species of Pegantha should therefore be accepted with due reservations. 



Most of the specimens of Pegantha in the Discovery collections are in a rather poor condition, but 

 some tolerably well-preserved specimens have enabled me to point out certain distinctive features, 

 which seem to be characteristic of the diflferent species and may be recognized even in fairly young 

 stages and in more or less mutilated specimens. Five species are represented in the collection, and 

 I refer them to five species which have previously been described in a recognizable way, doing away 



