762 Proceedings of Royal Society of Edinburgh. [sess. 
Description : — The umbrella is somewhat conical, with a rounded 
summit, the upper half a thick mass of jelly ; its cavity is very small. 
The velum is narrow. The stomach is upon a funnel-shaped peduncle. 
The base of the peduncle is 5 mm. in diameter, and tapers off to 
about 1 mm. ; its length is about 4 mm. The stomach projects 
a little way beyond the margin of the umbrella ; it is small, and 
has four perradial lobes. The mouth has four lips and its margin 
is slightly folded. Four narrow radial canals. The gonads are 
linear, and are situated upon the outer two-thirds of the radial 
canals upon the sub-umbrella, but do not quite extend to the 
circular canal. Upon the margin of the umbrella there are 
altogether sixty tentacles and bulbs ; their number in the respective 
quadrants being 12, 16, 17, 15. The tentacles are very much 
contracted, and it is difficult to make sure whether some of the 
smaller bulbs have tentacles or not, but half the bulbs certainly 
have tentacles. The perradial, interradial, and adradial tentacles 
are much larger than the others, which vary very much in size. 
Some of the bulbs have excretory pores on their inner side, just 
above the velum. Probably all of them have excretory pores, but 
owing to contraction the papillae are not visible. Marginal cirri 
absent. There are forty-nine marginal sensory vesicles, their number 
in the respective quadrants being 11, 11, 13, 14. Each vesicle has 
usually two otoliths ; a few (the smallest in size) have one otolith, 
and three were seen with three otoliths. 
Colour. — Stomach and bulbs pale brownish. By transmitted 
light, yellowish. 
Size. — Umbrella 7 mm. in length and 10 mm. in width. 
Melicertidium octocostatum (Sars). (Tables I. 10; II. 15.) 
Stomobrachium octocostatum , Forbes, 1848, p. 30, pi. iv. 
In 1901, a specimen was taken on 28th May and another on 
6th June. 
In 1902, it was first taken on 20th May, and last seen on 11th 
October. The specimens taken in May were adults. In July young 
stages and also adults were seen. It was generally very scarce. 
On 9th September two specimens were taken in Lamlash Bay. 
In August 1897, this medusa was abundant in Lamlash Bay. 
