40 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



record of the finding of the Dinoflagellate, Amphidinium 

 operculatum (previously unknown in Britain), on the beach at 

 Port Erin a couple of years ago. Since then it has been present 

 in great abundance at Port Erin on many occasions ; Mr. R. D. 

 Laurie found it at Hoylake, near Liverpool, in February, 1913 ; 

 two of our young Liverpool zoologists (R. J. Daniel and 

 J. Erik Hamilton), now at the Belmullet Whaling Station, 

 co. Mayo, inform me that they have noticed it on the shores of 

 Blacksod Bay ; and now I have to-day found it here in 

 abundance, staining slightly in patches and streaks the beautiful 

 white shell-sands of Iona. 



" Both the forms found at Port Erin — viz., the shorter 

 discoid (the typical A. operculatum) and the larger more ovate 

 form, which I have described from Port Erin — occur here, 

 associated with a few Naviculoid diatoms. 



" It seems probable that this curious Dinoflagellate, 

 known in the living state, so far as I can ascertain, to very few 

 biologists, and previously recorded from only three or four 

 far-distant localities, is really very generally distributed, and 

 might be found by careful searching on many sandy beaches. — 

 W. A. Herdman. S.Y. ' Runa,' Sound of Iona, July 20th." 



The two forms of Amphidinium referred to in the above 

 letter are shown at h and * in fig. 6, repeated here from last 

 year's report. These two forms, differing so considerably in 

 size, shape and movements, have now been found together at 

 the following localities :— Port Erin (Herdman), Hoylake 

 (Laurie), Cullercoats (Meek), Blacksod Bay (Daniel and 

 Hamilton), and Iona (Herdman). If they prove, as seems 

 quite probable, to be two distinct species, the small discoid 

 one (i, in fig. 6) is A. operculatum, Clap, and Lach., and the 

 larger more elongated form (h, in fig. 6), which was described 

 and figured fully in last year's report (p. 31, fig. 9), will require 

 a new name. 



As a further contribution to this fascinating subject — the 



