NARCOMEDUSjE — PEGANTHA. 445 



This medusa appears to belong in the genus Pegantha rather than in Sohnaris, for its 

 gonad extends outward in saccules from the subumbrella floor of the stomach. The typical 

 specimens are from the Hawaiian Islands and Pacific Ocean, but a closely allied, if not 

 identical, medusa is described by Haeckel from the China Sea under the name Sohnaris 

 astrozona. Haeckel had only one (half-grown ?) specimen and this had only half as many gen- 

 ital pouches, but the same number of tentacles and lappets as in P. punctata. 



Bell shield-shaped, 90 mm. wide, 25 mm. thick. 24 short, thick tentacles hardly half as 

 long as bell-radius. 24 marginal lappets, semicircular, 6 to 9 sense-clubs on each lappet. 

 The gonad consists in a ring of subumbrella saccules upon the subumbrella floor of the stomach, 

 there being a single saccule in each lappet radius, alternating thus with the radii of the ten- 

 tacles. The gonad is also diffusely developed over the ectodermal floor of the subumbrella 

 under the stomach. The medusa is colorless. Hawaiian Islands, tropical Pacific. 



Pegantha cyanostylis. 



Polyxenia cyanostylis, Eschscholtz, 1829, Syst. der Acalephen, p. 119, taf. 10, fign. 1 a- \c .—Haeckel, 1879, Syst.der Medusen, 



p. 330. 

 Polvxenia cyanolina, Haeckel, Ibid., p. 330. 



( >) Mollicina, medusa, Forskal, 1775, Descript. animal, itin. orient., p. 109; Icon., tab. 33, fig. c. 

 ( >)Foveolia mollicina, de Blainville, 1834, Man. d'Actinologie, p. 280, plate 33, fig. I. 

 {>)Foveolia diadema, Peron et Lesiteur, 1809, Annal. Mus. Hist. Nat., tome 14, p. 340. 

 ( ?) Mquorea cyanogramma, Quoy et Gaimard, 1824, Voyage de 1' Vranie, etc., p. 563, plate 84, figs. 7, 8. 



The typical specimens are described by Eschscholtz and Haeckel from the north of the 

 Azores and from the Canary Islands, but P. cyanolina Haeckel, from the Indian Ocean, 

 appears to be the same medusa in a young stage wherein there are but 13 to 15 sense-clubs 

 on each lappet margin instead of 25 to 30, and 4 instead of 8 folds in each genital sac in each 

 lappet radius as in P. cyanostylis. Haeckel's P. cyanolina is only 20 mm. wide, whereas the 

 Atlantic medusa is about 60 to 80 mm. wide. 



Foveolia mollicina and F. diadema Peron and Lesueur and Mquorea cyanogramma Quoy 

 and Gaimard are so vaguely described that their identity must remain in doubt, but they are 

 closely related to, if not identical with, P. cyanostylis. If they be identical with P. cyanostylis, 

 this medusa is of world-wide distribution throughout warm and tropical seas, a condition 

 commonly observed among species of Trachymedusae and Narcomedusae, which, being 

 independent of the conditions afforded by a shore for their development, range widely over 

 the open ocean. This subject is ably discussed by Maas, 1893, Natural Science, London, 

 vol. 2, pp. 92-99. 



P. cyanostylis may be described from the accounts of older authors as follows: Flat and 

 bell-shaped, about 40 to 50 mm. wide and 20 to 30 mm. high. There are 16 to 18 tentacles, 

 each about as long as the bell-diameter. 16 to 18 marginal lappets, each twice as long as 

 wide and somewhat rectangular in shape. 13 to 30 marginal sense-clubs upon each lappet- 

 margin. The gonads are found in a peripheral zone of small sickle-shaped, or halt-moon-like, 

 folded sacs, one of which is found in each lappet-cavity. The medusa is colorless or light 

 bluish. It is found in the tropical Atlantic. It may be identical with P. triloba. 



Pegantha clara R. P. Bigelow. 

 Pegantha clara, Bigelow, R. P., 1909, Biological Bulletin, vol. 16, p. 80, 2 figs. 



Bell lenticular, doubly convex, 53 mm. wide, 20 mm. thick, exumbrella smooth. 28 bell- 

 lappets, all similar each to each, alternating with 28 tentacles spaced at equal distances apart. 

 14 of these tentacles are long and range between 33 to 56 mm. in length; and they alternate 

 with 14 smaller tentacles ranging in length from 11 to 35 mm. The insertions of the long set 

 of tentacles are farther upward (above the margin) and inward (toward the center) than are 

 the insertions of the short tentacles. The tentacles taper gradually to their pointed tips and 

 their entodermal cores are composed of a row of chordate cells. The sensory-clubs appear to 

 have been destroyed by the formalin in which the medusa is preserved; but there are 2 to 5, 

 usually 3, long, slender, linear, somewhat tortuous, sensory tracts (otoporpae) which extend 

 from the bell-margin about half the distance up the exumbrella side of each lappet. 



