182 



Papers from the Department of Marine Biology. 



Aurellia aurita (Linnaeus). 



Medusa aurita, LINNJEUS, 1758, Systema Naturae, ed. 10, tomus 1, p. 660. 



Aurellia flavidula, PERON ET LESUEUR, 1809 Annal. du Mus. Hist. Nat., Paris, tome p. 14, 369. 



Aurelia aurita, LAMARCK, 1817 Hist. Anim. sans Vert., tome 2, p. 513. 



13 specimens of this universally distributed medusa were found by the 

 Albatross among the Philippine Islands. 11 half-grown specimens are from 

 station D 5663, December 28, 1909, in Macassar Strait, depth 11 fathoms, 

 about 1.7 miles off Kapoposang Island, 7 h 20 m p. m. 2 larger but still imma- 

 ture from Station D 5662, December 21, 1909, Flores Sea, near Tana Keke 

 Island, 5 h 40 m to 6 h 12 m a. m. 



Aurellia labiata Chamisso and Eysenhardt 



Aurelia labiata, CHAMISSO X:ND EYSENHARDT, 1820, Nova Acta Phys. med. Leop. Car., tome 10, 

 p. 358, planche 28, figs. 1 A. B. MAYER, 1910, Medusa; of the World, vol. 3, p. 628, fig. 

 398. LIGHT, 1914, Philippine Journal of Science, vol. 9, p. 200. 



Light, 1914, records a specimen of this medusa from the Philippines the bell 

 of which was 225 mm. in diameter, 107 mm. across the gonads, and with each 

 mouth-arm 100 mm. long. 



Aurellia labiata is distinguished from A. aurita by having 16 notches in its 

 bell-margin, by its peculiar velum-like, inter-rhopalar, subumbrella mem- 

 branes representing the true bell-margin, and by the very small size of its 

 subgenital ostia. The mouth-arms are also shorter than one commonly 

 observes them to be in A. aurita, and the terminal branches of the radial-canals 

 anastomose to a greater degree than in A. aurita. 



The dimensions of three specimens obtained by the United States Fisheries 

 Bureau steamer Albatross at Masbate Anchorage, Philippine Islands, on April 

 21, 1908, are as follows: 



Four other specimens were caught at night upon the surface under the 

 electric light, at Jolo Anchorage, on February 8, 1908. 



An abnormal but perfect specimen of Aurellia aurita was found at Tortugas, 

 Florida, on July 27, 1914. This aberration closely resembled the normal 

 A. labiata of the Pacific. There were 16 deep notches in the bell-margin, 8 

 perradial and 8 interradial, and the velum-like marginal membrane was like 

 that of A. labiata. The small subgenital ostia and simple mouth-arms also 

 recalled A. labiata, but the terminal branches of the adradial-canal system 

 did not anastomose and in this resembled A. aurita rather than A. labiata. 

 The case is interesting, as it leads one to suspect that A . labiata of the Pacific 

 has been derived as a mutation from the universally distributed A. aurita. 

 The bell of this Tortugas medusa was 270 mm. in diameter. Diameter of 

 genital cross 78 mm. Palps simple and each about one-eighth longer than 

 the bell-radius. 8 sense organs, 8 interradial notches in the bell-margin. 8 

 straight, simple, non-pig mented perradial-canals, 8 straight pink-colored inter- 

 radial-canals. The sparingly branched adradial-canals reach the bell-margin 

 without anastomosing and in this respect resemble those of A. aurita. The 

 male gonads were pink, the tentacles rich purple, the velarium creamy white, 

 the palps purple-pink, and the gelatinous substance pink. 



