﻿Medusce and Ctenophores from Firth of Forth. 305 



shaken, the medusae emitted flashes of pale greenish-white 

 light. During the night, if left in the dark, they seemed to 

 remain motionless at the bottom of the jar, but soon began 

 to pulsate and swim about when brought into a lighted 

 sitting-room. While the stimulation was probably due 

 primarily to light, the higher temperature of the room may 

 also have been a factor. 



Normally the number of tentacles is 16, as observed by 

 Forbes; but frequently they are not all developed, one or 

 more being then represented by a minute bulb — in one case 

 as many as seven were thus reduced. Johnston's original 

 specimen had but 13 tentacles. Of 33 cases noted by us, 

 nine had 16 tentacles, nine 15, five 14, six 13, two 11, one 

 (small) 10, and one 9. The presence of an extra bulb in 

 one of the normal specimens is the only indication we have 

 seen of the production of more than 16 tentacles. In life, 

 the tentacles were of a delicate rose-pink colour, which left 

 them, however, very soon after the application of the formalin. 



Under the name of Diancea hairdii this medusa was 

 described by Dr George Johnston from a specimen found 

 floating on the surface of the water in Berwick Bay on 27th 

 Sept. 18321; ^nd, "during the winter of 1839," Forbes {l.c) 

 met with it in the harbour at Burntisland, and also at St 

 Andrews, where it has since been taken on many occasions 

 (M'Intosh). Dalyell's figure (l.c) of a medusa he received 

 from a Cellardyke fisherman in the month of December, 

 from the neighbourhood of the Isle of May, clearly represents 

 a Tima hairdii. It is a better figure than Forbes's, which is 

 poor. This is essentially a winter medusa, reaching the 

 spawning state from November to January.^ The hydroid 

 stock from which it springs is not known, but probably it is 

 some Campanulariid, as in the case of the American form 

 mentioned by Louis Agassiz. In British waters it appears, 

 as yet, to have been recorded only from the east coast. On 

 the opposite side of the North Sea it has been taken at 

 Heligoland by Hartlaub. 



1 Loudon's Mag. Nat. Hist., vol. vi. (1833), p. 320, pi. 41. 

 ^ On 16tli March 1909, large numbers were stranded on the beach east of 

 North Berwick. 



VOL. XVII. 2 A 



