853 
Genus Actinoptychus Ehrenberg. 
A. undulatus. (Kiitz.) Stomachs of Noctilucae, Yarmouth ; 
Breydon ditches, Hunstanton, and Wells. 
Genus Melosira Agardh. 
M. va rians. Ag. Common — in most fresh-water ditches. 
M. borrerii. (Grev.) Pure in a brack ish- water ditch, Breydon. 
Genus Orthosira Thwaites 
O. arenaria. (Sin.) Frequent in a ditch at Ilcllesdon, but rare 
in other localities. 
0. oricualcea. (Sin.) Frequent in fresh-water ditches. 
0. marina. (Sm.) Stomachs of Hoctilucai, Yarmouth. 
O. punctata. (Sm.) Ormesby Broad — rare. 
Genus Dendroteres Ehrenberg. 
D. spiralis. (Ehr.) Bare — in moss from an elm on Earlham 
Boad. 
Genus Pouosira Ehrenberg. 
P. maculata. (Sm.) Breydon ditches. 
Family CILETOGERIEE. 
Genus Ch.etoceros Ehrenberg. 
C. wighamii. (BrL) In a ditch near “ The Berney Arms,” 
Breydon. 
C. bacteriastrum. (Wallicli.) Stomachs of Noctilucai, l*ar- 
mouth. 
C. armatum. (West.) Yarmouth sands : a very doubtful diatom. 
It may sometimes be found forming a greenish-brown 
pellicle, on the wet sand, at low water. 
Genus Bhizosolenia Ehrenberg. 
B. styliformis. (BrL) \ 
B. imbricata. (Bri.) f 
B. setigera. (Bri.) [ 
B. alata. (Bri.) 
Stomachs of Boctilucie, l r annouth. 
