W. WEST AND G. S. WEST ; ALGA-PLORA OF YORKSHIRE. 201 



S.VV. — Cusworth, near Doncaster. Doncaster town water ; 

 Hatfield district ; Rossington (M. H. Stiles). 



Mid W. — I.angcliffe, near Settle. Malham Tarn Bog. 



S.E. — -Beverley. Hornsea Mere; Risby Pond; Wawne ; 

 Hornsea Peat Deposit (G. Norman). 

 Var. binodis Grun. 



[Syn. Odontidium parasiticiim W. Sm., pro parte]. 



Mid W. — Pond at Horsforth ! (Miss J. Town), attached to 

 SiiiirelLi biseriata and Cyinatopleiira Solea. 



S.W.— Roche Abbey (M. H. Stiles ; J. N. Coombe). 



S.E. — Market Weighton Canal; Beverley Parks (G. Norman). 



969. Fragilaria Harrisonii (W. Sm.) Grun. 



[Syn. Odontidium Harrisoni W. Sm.]. 



S.W.— Cusworth district (M. H. Stiles). Roche Abbey (J. N. 

 Coombe ; M. H. Stiles). 



Mid W. — Langcliffe, near Settle. 



S.E. — Haltenprice ; Spring Head ; Hornsea Peat Deposit ; 

 Spring Ditch ; Cottingham ; near Hull (G. Norman). 



970. Fragilaria mutabilis (W. Sm.) Grun. 



[Syn. Odontidium mutabile W. Sm.]. 



S.W.— Cusworth district (M. H. Stiles). Marsden. CuUing- 

 worth. Roche Abbey (M. H. Stiles; J. N. Coombe). Fixby. 



Mid W. — Holden Gill, near Keighley. Baildon. Staveley 

 Dam, near Knaresborough. Ribblehead. 



N.W.— Howgill Fells. Great Shunnor Fell. 



N.E. — Saltburn. Scarborough. 



S.E.— Beverley. Waghen. Loftsome Bridge, near Wressle. 

 Risby Pond; Wawne; Market Weighton Canal ; Cottingham; 

 Spring Ditch (G. Norman). 



Family MERIDIONIDM. 

 Genus MERIDION Ag., 1824. 



971. Meridion circulare (Grev.) Ag. 



S.W.— Cusworth and Hatfield districts ; Roche Abbey ; Don- 

 caster town water (M. H. Stiles). WooUey. Saltaire. Marley, 

 near Bingley. Elslack. Coley, near Shelf (pure gathering). 



