760 Proceedings of Royal Society of Edinburgh. [sess. 
specimens as a new species I should like to see another specimen 
with gonads, so I shall leave the specific name in abeyance. 
When a Margelis is just taken out of a tow-net it usually has 
its tentacles more or less contracted. Occasionally a specimen is 
found with all its tentacles rigidly contracted, forming mere stumps 
or lobes round the margin of the compound basal bulb. When a 
specimen in this condition is placed in a glass of sea water, the 
tentacles, within a few hours, begin to expand, and nearly always 
those at the corners of the basal bulbs are the first to expand. At 
this stage the medusa may have one or two tentacles expanded on 
each of the four bulbs. Now Forbes’s figure of Bougainvillia 
nigritella (Monograph, pi. xiii. fig. 2) shows basal bulbs with 
only one tentacle, and the tentacle is not in the middle of the 
bulb, but at one end. In the description of the species Forbes 
says, — “It (the umbrella) is contracted at its opening, which is 
quadrangular, each angle bearing a compact, oblong, or almost 
kidney-shaped mass of tentacular bulbs, apparently four in 
number, closely united together, so that, but for the indications of 
lobations at the lower part of the pad, the number of these bodies 
would be indeterminable. On one side of each pad arises a very 
short, thick, yellow tentacle, and only one.” It is clear from 
Forbes’s description that he was describing a Margelis which had 
four out of five tentacles in a state of contraction, though the 
figure itself (like many other figures in that monograph) is not so 
clear and defined as the text. It was an error on the, part of 
Haeckel to place this species in the genus Thamnitis. 
Tiara pileata (Forskal). (Tables I. 16 ; II. 19.) 
Tiara yileata, Haeckel, 1879, p. 58, taf. iii. 
In 1901, it first appeared about the middle of July and dis- 
appeared about the middle of October. 
It was fairly common in Lamlash Bay on 14th September. 
In 1902, it was taken from the middle of July till the beginning 
of October. Within the Cumbrae area it was very scarce ; only 
five specimens were taken. On 9th September a few specimens 
were taken in Lamlash Bay, and on 11th September it was fairly 
common in Etterick Bay, on the west side of Bute. 
All the specimens taken in 1901 and 1902 belonged to early 
