104 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



fully 2,000 cubic centimetres. Some of the Noctiluca and 

 Pleurobrachia were placed in a small tank of sea water, but 

 without circulation. The Pleurobrachia died off after a couple 

 of days. The Noctiluca lived and retained their phosphorescent 

 character for three weeks. The organisms were examined for 

 food contents. The Noctiluca were all quite empty and thus 

 differed from those collected at Port Erin at the end of July 

 which were completely tilled with the diatom Rhizosolenia 

 stolterfothii. With the exception of one Pleurobrachia all the 

 ctenophora examined had no food in the stomodaeum. 

 A perfect specimen of the amphipod Calliopius Iceviusculus 

 (Kroyer) was found in the stomodaeum of one of the 

 Pleurobrachia. This amphipod was recorded by A. 0. Walker 

 as long ago as 1889 from collections of plankton taken at low 

 water at Puffin Island where it was very abundant. The 

 species is widely distributed in the northern hemisphere, and 

 is usually moderately abundant in shallow water among algae. 

 The amphipod was quite fresh and evidently recently captured. 

 On the 17th December — 24 hours after these large collections 

 were made — the whole area was again examined and only 

 one Pleurobrachia was found. There was no Noctiluca in the 

 plankton. The following day another investigation was made 

 and nothing at all could be found of the Noctiluca and ctenophore 

 invasion of the 16th December. 



It is quite unusual to find an abundance of Noctiluca and 

 ctenophora in our area in mid-winter. Immense visits of 

 Noctiluca along the coasts of North Wales and Lancashire have 

 been recorded by us at various times, but they have all been 

 some time between the beginning of August and the end of 

 September A few specimens may be present in some part 

 of the Irish Sea at almost any time. Noctiluca was present 

 in small numbers in the plankton collected at Port Erin in 

 November and December, 1919. We do not know what the 

 plankton between Lancashire and the Isle of Man was like 



