W. WEST AND G. S. WEST! ALGA-FLORA Ol' YORKSHIRE. 187 



Genus RHOICOSPHENIA Grun.. i860. 



921. Rhoicosphenia curvata (Kiitz.) Grun: 



[Syn. Goinphonema curvatuvi 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). Markington 

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



N.W.— Holwick. Romaldkirk. 



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

 Mai ton. 



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

 (G. Norman). 



922. Rhoicosphenia fracta (Schum.j Rabenh. 



[Syn. Gomphoiieina fraction Schum.]. 

 S.W. — Cullingworth. Kildwick. 

 Mid W.^Adel Bog. 



Family ACHNANTHE.E. 

 Genus ACHNANTFIIDIUM (Kutz.) Grun., 1880. 



923. Achnanthidium flexellum (Kiitz.) Breb. 



[Syn. Cocconeis Thivaitesii W. Sm.]. 



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

 Clough, with auxospores and sporangial valves. Cusworth, 

 near Doncaster! (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 coarctation Breb.]. 

 S.W.— Bingley. 



