W. WEST AND G. S. \VESt : ALGA-FLORA OF YORKSHIRE. 1 55 

 Genus CCELOSPH^RIUM Nag., 1849. 



771. Coelosphxrium Kiitzingianum Nag. 

 Mid W. — Ingleborough. 



N.W. — Jervaulx Abbey. 



Genus G0MPH0SPH.«RIA Kiitz., 1836. 



772. Gomphosphseria aponina Kiitz., 1836. 

 Mid W.— Cam Fell (viii. 1896). 



N.E. — ^Pilmoor, near Thirsk. 



Genus CLATHROCYSTIS Henfrey, 1856. 



773. Clathrocystis aeruginosa (Kiitz.) Henfrey. 

 Mid W. — Pond, Boston Spa (iv. 1897). 



S.E. — Hornsea Mere, very fine. 



774. Clathrocystis roseo-persicinus (Kiitz.) Cohn. 

 [Syn. Proiococcus roseo-persicinus Kiitz. ; Polycystis 

 roseo-persicinus (Kiitz.) Gutw., 1895]. 



S.W.^Bradford (ix. 1896). 



N.E. — Pilmoor, near Thirsk. Malton. 



Genus POLYCYSTIS KUtz., 1845. 



775. Polycystis marginata (Menegh.) Richter. 

 \^yn. Microcystis marginata {Menegh.) Kiitz.; Ana- 

 cystis marginata Menegh.]. 



Mid W.— Old Cote Moor (viii. 1896). 



776. Polycystis elabens (Br^b.) Kiitz. 

 Mid W. — Roundhay Park, Leeds. ' 



N.E. — Pilmoor, near Thirsk. Carlton Bank. 



777. Polycystis Flos-aquse Wittr., 1879. 

 Mid W. — Boston Spa. 



778. Polycystis viridis A. Br., 1867. 

 N.E. — Pilmoor, near Thirsk. 



This species has not previously been recorded for the feritish 

 Isles. 



Genus GLCEOCAPSA KUtx., 1843; em. Nag., 1849. 



779. Gloeocapsa didyma Kiitz. 

 Mid W. — Helln Pot, near Selside. 



