394 



MEDUSAE OF THE WORLD. 



Bigelow, 1909, records the capture of 9 specimens in the eastern tropical Pacific by the 

 Albatross, between 300 fathoms and the surface, and his description of the medusa is the 

 best yet published. His photographs show a simple, round mouth-opening such as is found 

 in Halicreas, not four lips as are seen in Homoeonema. 



Maas maintains that this species belongs to his genus Homoeonema, but he does not re- 

 describe the medusa and does not state that 4 lips are present. VanhofFen's beautiful figure 

 shows a round mouth-opening and this would oblige us to place the medusa in the genus 

 Halicreas. It is very much larger than" Homoeonema" platygonon of Maas, being about 35 mm. 



247- 



Fig. 247.— Halicreas (Haliscera) alba. Fig. 248.— Halicreas (Haliscera) conica. 



Above figures after Vanhbffen, in Tiefsee Expedition, Valdivia. 



wide instead of about 4 mm. as in H. platygonon; and while future studies may show that the 

 widely distributed H. alba is identical with the Arctic "Homoeonema" platygonon, the published 

 evidence now available does not appear to me to warrant such a conclusion. 



Halicreas conica. 



Haliscera conica, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 3, Lfg. 1, p. 72, taf. 

 9, fig. 6; taf. n, fig. 33.— Maas, 1906, Fauna Arctica, Bd. 4, Lfg. 3, p. 493. 



Bell 18 mm. wide, flatter than a hemisphere, with an apical projection. 8 oval gonads in 

 middle of the 8 broad radial-canals. 72 tentacles, of uniform size. 16 lithocysts ( ?), 2 in each 

 octant. Velum well developed. Colorless. Indian Ocean, depth of 500 to 1,000 fathoms. 

 Beautifully figured in VanhofFen's report on the veiled medusae of the German Valdivia expe- 

 dition. 



Genus HALITREPHES Bigelow, 1909. 



Halitrephes, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 145. 



The type species is Halitrephes maasi Bigelow, of the eastern tropical Pacific. 



GENERIC CHARACTERS. 



Similar to Halicreas, but with more than 8 radial-canals. 



Halitrephes maasi Bigelow. 

 Halitrephes maasi, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 146, plates 33, 45. 



Bell 55 mm. wide. Exumbrella smooth, low, rounded and without exumbral papillae. 

 Gelatinous substance thin and brittle. About 70 tentacles of various sizes. All with thick, 

 flexible, proximal parts and relatively stiff, narrow, straight, outer halves, covered thickly 

 with nematocysts as in Halicreas. A few lithocyst-clubs on the bell-margin between the 

 tentacles. Central stomach 15 mm. wide, mouth-opening round. 28 broad radial-canals 

 arise from stomach and 5 fork dichotomously so that ^ canals extend to the circular ves- 

 sel. Gonads small, flat, and circular and close to the periphery of the stomach. Medusa 

 colorless. Described by Bigelow from the Albatross collection of 1904-05. 3 specimens 

 found off" the coast of Peru, between 300 fathoms and the surface. 



Genus BOTRYNEMA Browne, 1908. 



Botrwema, Browne, 1908, Trans. Royal Soc. Edinburgh, vol. 46, p. 239. 



The type species is Botrynema brucei of the Antarctic Ocean. 



