MEDUSA. 48 
December, 1899, and January, 1900. The ice was then breaking up and departing 
from the coast. The temperature of the sea at the surface was 29° to 30°F. These 
specimens were evidently ruined by bad storage. It is sad to see large specimens in 
such an unsatisfactory condition, especially when the correct determination of the 
species is of importance. 
The ‘Discovery’ obtained a single specimen on Ist August, 1902. It was 
captured by hand in McMurdo Sound. This specimen also got broken into pieces. 
The occurrence of Periphylla at or near the surface in the icy Antarctic region is 
very interesting, because it is not a surface-seeking Medusa in the Atlantic or Pacific, 
but prefers to inhabit the intermediate and deeper zones of those oceans. I have but 
little doubt, from the appearance and condition of the internal organs, that these 
specimens were alive and in healthy condition when taken out of the sea; and that 
they were not dying specimens, as Vanhéffen has suggested, or ones washed up from 
the depths of the Antarctic Ocean. 
Haeckel, from the material collected by the ‘Challenger,’ described and figured in 
great detail two new species of Periphylla, namely, P. mirabilis, of which a single 
specimen was taken in lat. 40° 28’ §., long. 177° 43’ E. (off the east coast of New 
Zealand); and P. regina, a single specimen of which was found south-west of the 
Kerguelen Islands (lat. 62° 26’ S., long. 95° 44’ E.). 
Messrs. Maas and Vanhdffen recognise three species of Periphylla, namely, 
P. hyacinthina, Steenstrup, P. dodecabostrycha (Brandt), and P. regina (Haeckel). 
Periphylla mirabilis is considered by Maas (1897) and by Vanhéffen (1902) to be 
identical with P. dodecabostrycha. 
According to Prof. Haeckel’s description and figures, the rhopaliar pedalia of 
P. mirabilis are shorter than the tentacular ones. It seems to me that he has divided 
the rhopaliar pedalia into two parts by a transverse groove. In the ‘ Challenger’ type 
specimen of P. mirabilis the groove is more like a crease on the surface of the jelly 
than a natural groove. If one disregards this crease, then the rhopaliar pedalia are 
longer than the tentacular pedalia, and are similar in shape to those on the specimens 
in the two Antarctic collections, and also similar to the pedalia of P. hyacinthina 
(Haeckel, 1880, Taf. xxiv.). 
The ‘Challenger’ type specimen of P. regina in the British Museum consists of 
a few fragments. From a scientific point of view these fragments are of little value, 
and can now be looked at only as objects of historical interest. 
The description and figures of P. dodecabostrycha, as first given by Brandt (1838), 
are based upon a large specimen about 200 mm. in length and width. The specimens 
taken by the recent exploring expeditions have usually been small ones, not larger 
than 27 mm. in height and 18 mm. in width. Mr. Bigelow (1909) has put 
forward good reasons for regarding the small specimens of P. dodecabostrycha, 
described by Messrs. Mass and Vanhiffen, as young and less pigmented forms 
of P. hyacinthina. 
VOL, Ve 2B 
