200 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



obtained at Station D5220, April 24, 1908, on the surface between 

 Luzon and Marinduque at 12.57 p. m. These are all small and about 

 10 mm. in diameter, evidently being taken from a swarm of immature 

 individuals. 



Genus CHRYSAORA Peron and Lesueur, 1809. 



Chrysaora Peron and Lesueur, 1809, Annal. du Mus. Hist. Nat., Paris, vol. 14, 

 p. 364.— Mayer, 1910, Medusae of the World, vol. 3, p. 577. 



Generic Characters. — Pelagidae with 8 marginal sense-organs, 24 

 (3X8) tentacles, and typically 32 (4X8) marginal lappets; although 

 in C. malanaster the lobes may still further divide, giving 48 (6X8) 

 marginal lappets. 



CHRYSAORA MELANASTER Brandt. 



Chrysaora melanaster Brandt, 1838, Mem. Acad. Sci. St. Petersburg, Sci. 

 Nat., ser. 6, vol. 4, p. 385, pis. 16, 17— Maver, 1910, Medusae of the 

 World, vol. 3, p. 582. 



There is a well-preserved specimen of this medusa from station 

 D5461, June 14, 1909, San Miguel Bay, east coast of Luzon, depth 11 



fathoms (Cat. No. 28712, U.S.N.M.). 

 The bell is about 130 mm. in diam- 

 eter and slightly flatter than a 

 hemisphere. There are 16 radiating 

 spoke-like streaks of faint umber 

 color extending from near the apex 

 of the exumbrella to the bell-margin 

 in the radii of the 16 cleft velar 

 lobes. These 16 streaks occupy de- 

 pressed radial areas sunken below 

 the general level of the contour of 

 the exumbrella, and they are be- 

 sprinkled coarsely with wart-like 

 nematocyst clusters of cinnamon-brown color. 



There are 8 rhopalia, 3X8 tentacles, and 6X8 marginal lobes. The 

 velar lobes are cleft as in Brandt's figures and are nearly similar in 

 shape and size to the ocular lappets. They are, however, not nar- 

 rower at the base than outwardly, as in Brandt's figures, but are oval 

 and taper quite regularly from base to tip. 



The tentacles are short and slender, the longest being not over 

 60 mm. 



The mouth-arms are long and slender, folded complexly, and about 

 170 mm. long. The gonads are well developed, apparently mature, 

 and protrude through the subgenital ostia, the subgenital ostia being 

 fully twice as wide as the perradial columns between them. Thus 



Pig. 8. — Chrysaora melanaster. 

 octant of the bell margin. 



An 

 San- 



Miguel Bay, east coast of Luzon. 



