38 EDWARD T. BROWNE. 
at least double the number of sense organs. I could not find a single specimen in the 
collection with the characteristic conical umbrella of S. bitentaculata. S. mediterranea 
is a colourless Medusa, and Mr. Hodgson informed me that the ‘ Discovery ’ specimens 
were colourless when alive. S. bitentaculata, on the other hand, has reddish gonads 
and tentacles, but the colour disappears after preservation. 
SoOLMUNDELLA MEDITERRANEA. 
Aiginopsis mediterranea, J. Miiller, 1851, p. 272, Taf. XI. ; Leuckart, 1856, p. 33, Taf. II.; Metschnikoff, 
1874, Bd. xxiv., p. 26, Taf. IV. ; Haeckel, 1879, p. 852 ; Lo Bianco, 1904, p. 56, Taf. XXXV., 
fig. 142. 
Solmundella mediterranea, Maas, 1906, p. 12, Taf. I. (fig. 5), Taf. IIT. (figs. 28, 24). 
Solmundella muellert, Haeckel, 1879, p. 352. 
Solmundella henseni, Maas, 1893, p. 55, Taf. V., fig. 11. 
The ‘ Discovery’ collection contains about 300 specimens of this species, but only 
a few are in a satisfactory condition, and all are more or less contracted. It was by 
far the commonest Medusa in McMurdo Sound. In 1903 specimens were taken from 
the middle of March throughout the Antarctic winter up to the beginning of 
November. Young and adult stages frequently occurred together, and apparently the 
Medusa has no definite breeding season. 
In the ‘Southern Cross’ collection there are three specimens of Solmundella, 
which no doubt belong to this species. They were taken at Cape Adare on 10th 
May, 1899. 
The umbrella is a little broader than high, with a rather flat top, about on a level 
with the exit of the tentacles. The umbrella of the largest specimens measured 7 mm. 
in diameter. Over the ex-umbrella there are scattered many small clusters of cells, 
which are especially noticeable near the margin of the umbrella. These are ectodermal 
cells containing many well-defined granules, and amongst these cells are generally a 
number of nematocysts. 
There are four peronial grooves in the wall of the umbrella. The groove below 
each tentacle is of the normal type, but the groove in each of the perradii without 
tentacles is in a rudimentary condition. Prof. Maas (1905), p. 72, figs. 74 and 75, 
mentions and figures slight peronial grooves in the perradii without tentacles in 
S. bitentaculata, taken by the ‘Siboga’ expedition in the East Indies, and he includes 
the presence of four radial grooves in the generic character. The specimens which 
I examined of the same species taken off Ceylon (Browne, 1905, p. 153) did not show 
a groove in the perradii without tentacles. 
The Antarctic specimens have very conspicuous grooves in the perradii without 
tentacles. The grooves cut deep into the jelly at the margin of the umbrella, but the 
length and depth of the groove show a considerable amount of variation. The 
peronial band in each of the perradii without tentacles, after running alongside the 
sub-umbrella turns off at the level of the stomach to the ex-umbrella, where there is 
