MEDUSA. 47 
Distribution.—Pacifie Ocean: off the coast of Chile (Vanhéffen, 1892), off the 
coast of Central America (Maas, 1897), off the Hawaiian Islands (Mayer, 1906), off 
New Zealand (Haeckel, +1880). 
Famity ATOLLIDA. 
Genus Atouua, Haeckel, 1880. 
(sens. em. Vanhdéffen, 1902, Maas, 1897-1904.) 
ATOLLA WYVILLIL. 
(Plate VII, fig. 2.) 
Atolla Wyvillet, Haeckel, 1880, p. 488 ; id., 1882, p. 113, Pl. XXIX., figs. 1-9 ; Vanhéffen, 1902, p. 13, 
Taf. V., fig. 22; Browne, 1908, p. 241; Bigelow, 1909, p. 39. 
There is one specimen of this Medusa in the ‘Discovery’ collection. It was 
taken in lat. 70° 30'S., long. 169° E., off Admiralty Range (near Cape Adare), in a 
trawl (bottom at 610 fms.), on 26th February, 1904, when the ship was among 
pack ice. 
The aboral side of the umbrella is in good condition, but the oral side is damaged. 
The stomach is torn, and only two of the gonads remain. The jelly is of a dark green 
colour, which is due to fixing with chromic acid, but the dark reddish brown pigment, 
which should coat the greater part of the umbrella, has been rubbed off, and only 
traces of it now remain in grooves, depressions, and other more or less protected 
places. 
This species has been very well described and figured by Prof. Haeckel. It is 
distinguished from the other species of the genus by the presence of conspicuous 
lobes, separated by broad furrows around the margin of the central disc of the 
umbrella. The specimen shows this character very clearly. It has 21 lobes 
separated from each other by a broad, deep U-shaped furrow. 
The width of the umbrella is about 77 mm. and the height about 20 mm. The 
top of the central disc is probably not perfectly flat, but slightly convex; its 
diameter measured 46 mm. There are 22 tentacles and an equal number of sense 
organs. The pedalia of the tentacles measured 6 mm. in length and 7 mm. in 
width. The length of cesophagus is about 20mm. The diameter of circular muscle 
band is about 65 mm. 
Until Prof. Agassiz carried out in the ‘ Albatross’ (1904-05) his explorations in 
the Eastern Pacific, Atolla wyvillii was known from the Antarctic and sub-Antarctic 
regions only. Mr. Bigelow (1909), in his report on the Meduse collected by 
Agassiz’s expedition, records specimens from the neighbourhood of the Galapagos 
Islands, and from other stations. In the region explored <A‘olla occurs within 
300 fms. of the surface. , 
