W. WEST AND G. S. WEST : ALGA-FLORA OP YORKSHIRE. 187 

 Genus RHOICOSPHENIA Giun., i860. 



921. Rhoicosphenia curvata (Kiitz.) Grun. 



[Syn. Gomphonema curvatum Kiitz.]. 



S.W.— Hatfield district; Rossington (M. H. Stiles). Brad- 

 ford. Holbeck. Roche Abbey (M. H. Stiles; J. N. Coombe). 

 Shipley. Castleford. 



Mid W. — Baildon. Harrogate (G. Norman). Markingtoii 

 (Rev. J. S. Tute). Ingleton. 



N.W.— Holwick. Romaldkirk. 



N.E. — Staithes. Hayburn Wyke. Scalby Beck. Saltburn. 

 Malton. 



S.E. — Newsholme. Cottingham ; Reservoir waterworks, Hull 

 (G. Norman). 



922. Rhoicosphenia fracta (Schum.) Rabenb. 



[Syn. Gomphonema fraduin Schum.]. 

 S.W.— Cullingworth. Kildwick. 

 Mid W.— Adel Bog. 



Family ACHNANTHE.'E. 

 Genus ACHNANTIIIDIUM (Kiitz.) Grun., i88o. 



923. Achnanthidium flexellum (Kiitz.) Breb. 



[Syn. Cocconeis Thtvaitem W. Sra.J. 



S.W.— Askern district (M. H. Stiles). Bingley. Ogden 

 Clough, with auxospores and sporangial valves. Cusworth, 

 near Doncasterl (M. H. Stiles). Hebden Bridge., 



Mid W.— Dripping rocks, Shipley Glen, abundant. Dripping 

 rocks, Holden Gill, near Keighley. Ingleton. South of Cray 

 Moss. Adel (W. B. Turner). 



N.W.— Cautley Spout. Mickle and Cronkley Fells. 



N.E.— Staindale. 



S.E.— Newbald; Cottingham (G. Norman). 



Genus ACHNANTHES Bory, 1822. 



924. Achnanthes coarctata (Breb.) Grun. 



[Syn. Achnanthidium coarctatum Breb.]. 

 S.W.— Bingley. 



