10 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



A considerable amount of variation was noticed in the 

 relative numbers of certain species at the various expeditions 

 to Hilbre Island. As an example, the large Dendronotus 

 arborescens was almost absent from the shore early in the 

 summer (May), while in July it occurred in abundance. 

 This suggests that there is possibly a considerable amount 

 of migration from deep water on to the shore, and back 

 again, in the case of some species of molluscs and other 

 animals. 



The discovery of Clavelina lepadiformis at Hilbre is 

 interesting, as the Tunicata seem particularly rare in this 

 neighbourhood. Clavelina was dredged in abundance, during 

 August, off the south end of the Isle of Man, in deep 

 water. 



In the middle of June, Mr. James Poole, a member of 

 the Committee, offered to provide a tug, the " Spindrift," for 

 a dredging expedition on the 20th of June. The channel 

 between Hilbre Island and Point of Ayr, on the Welsh coast, 

 was chosen for exploration on this occasion, and, notwith- 

 standing very unfavourable weather, a considerable amount 

 of work was done. Dredging, trawling and tow-netting 

 were carried on in Hilbre Swash, in Welshman Gut, and in 

 a deep hole lying a short distance off Point of Ayr. In this 

 last locality, the following species amongst others were 

 obtained : — 



CcELENTERATA. — Hydractifiia echinata, Halecium haled- 

 num, Alcyonimn digitatum^ Actinoloba dianthus, 

 Lafoea dtwiosa, Sertularia abietina, Sertularia oper- 

 culata, Sertularia Jiliculaf Antennularia antennina. 

 PoLYzoA. — Idmonea serpens, Scrwpocellaria scrupea, 

 Amathia lendigera, Crisia eburnea, Alcyonidium 

 gelatinosum* 

 Crustacea. — Montagua alderi, Caprella linearis, My sis 



