768 Proceedings of Royal Society of Edinburgh. [sess. 
cysts. Sixteen large oval marginal sense-organs, containing many 
otoliths. The sense-organs are not closed vesicles, but open sacs. 
They are attached to the inner margin of the umbrella on their 
outer side and to the velum on their inner side. The opening 
is large and oval in shape, and is on the inner side of the velum, 
at its juncture with the umbrella. 
Colour. — Pale yellowish-brown for stomach, gonads, and basal 
bulbs (in formalin). 
Size. — Umbrella about 7 mm. in length and 10 mm. in width. 
Description of the specimen taken on 27th June : — The 
umbrella is watchglass-shaped, about twice as broad as high, 
with moderately thick walls. The umbrella is much thinner 
and flatter than in the one described above. The stomach is 
short and flat, with a quadrangular base. The mouth has four 
small lips. The gonads are linear, and extend over about three- 
quarters of the length of the radial canals, reaching almost to the 
margin of the umbrella. The ova are laterally situated upon the 
canals, and many are very large and ready for liberation. About 
forty-eight tentacles. Numerous cirri. Sixteen marginal sense- 
organs. 
Size. — Umbrella about 5 mm. in length and 10 mm. in width. 
Note on Mitrocomella fulva : — In my “ Report on some Medusae 
from Norway,” I described a new species of Mitrocomella called 
M. fulva. The specific characters are based partly upon a single 
specimen taken and examined alive at Plymouth in 1898, and 
partly on a single specimen in formalin from Byfjord, near Bergen. 
Both specimens are described, and the Norwegian one is figured. 
The intermediate stages of Mitrocomella polydiademata , which I 
saw alive at Port Erin (Isle of Man) in 1893 and 1894, had the 
mouth and basal bulbs of the tentacles of a purplish colour, and 
the gonads either yellowish-brown or purplish. Romanes de- 
scribed his specimens from Cromarty Firth with all the organs 
of a rich rose colour. The Plymouth specimen had yellowish- 
brown basal bulbs. When the specimens are once in alcohol or 
formalin the purple colour disappears, and a yellowish-brown 
colour is substituted for it, so that M. fulva is no longer 
distinguishable from M. polydiademata by its colour. After 
comparing the Millport specimens and some intermediate stages 
