

NOTES ON DTNOFLAGELLATES, ETC. 61 



flagellates. Several of these forms were figured in the reports 

 of 1911 and 1912 as varieties or different stages of Amphidinium 

 operculatum, but they have since been described by Kofoid as 

 distinct species and, as they seem to keep definitely to their 

 respective positions on the beach for considerable periods 

 without changing, it is probably more satisfactory to regard 

 them as species rather than varieties. The differences in form 

 are made clear in the accompanying outline sketches (p. 62). 



Amphidinium herdmani, Kofoid, corresponds to the 

 " short " form figured in the report of 1911 as A. operculatum. 

 It differs from A. operculatum as described and figured by 

 Claparede and Lachmann in 1868 in the size and shape of the 

 operculum. 



A. asymmetricum, Kofoid, is the same as the " long " 

 form of A. operculatum described in 1912. 



A. sulcatum, Kofoid, is not among the forms figured 

 in the previous reports, but occurred abundantly this summer. 

 It seems to be the only species of Amphidinium which remains 

 at the surface when covered by water. In the laboratory, 

 while A. herdmani and A. asymmetricum will live and multiply 

 on damp sand but do not flourish in the presence of too much 

 water, A. sulcatum will multiply in sea water alone to such 

 an extent as to form, in a few days, a thick slimy scum. 



Gymnodinium sp. ? was present in considerable numbers 

 over a very restricted area. It was found only in and close 

 to a trickle of rather fresh water draining down from behind 

 the harbour steps. (See Sketch Map, p. 63.) It was always 

 associated with large numbers of Diatoms, and was found 

 on the surface at all times of the tide. It also multiplied in 

 water in the laboratory. 



Polykrikos sp. ? occurred fairly regularly on certain parts 

 of the shore though never in such abundance as to cause 

 discolouration. (See Sketch Map.) 



Euglena spp. ? The two species of Euglena each occurred 



T.1 



