I So YORKSHIRE NATURALISTS' UNION'. 



N.W.— Mickle Fell. 



N.E.— Staithes. 



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



895. Navicula Gallica (W. Sm.) V.H. 



[Syn. Diadesmis Gallica W. Sm.]. 

 Mid W. — Near Kriaresborough. Wigton Moor. Malham 

 Tarn Bog. 



N.E. — Pilmoor, near Thirsk. Terrington. 



Genus COLLETONEMA (Breb., 1849) V.H. 



896. Colletonema lacustre (Ag.) V.H. 



[Syn. Schizoiiema lacustre Ag.]. 

 S.W.— Hatfield district (M. H. Stiles). 



Genus VANHEURCKIA Breb., 1868. 



897. Vanheurckia rhomboides(Ehrenb.) Breb. [Syn. 

 Navicula 7-homboides Ehrenb. ; Frustulia rhomboides 

 (Ehrenb.) De Toni]. 



Frequent in sphagnum bogs and peat bogs generally, some- 

 times occurring in pure gelatinous masses. 



S.W. — Thome Moor (G. Norman). Greetland, near Halifax. 

 Morley. Near Bradford. Cullingworth. Keighley Tarn. 



Mid W.— Milford; Blubberhouses (\V. B. Turner). Baildon. 

 Moughton Fell. Near Buckden. Ribblehead. Bowland Knotts. 



N.W.— Baugh Fell. Penhill Beacon. Lund's Fell. Mickle 

 and Cronkley Fells. Great Shunnor Fell. 



N.E.— Carlton Bank. 



S.E. — Skipwith Common (Rev. VV. Fowler!). 



Var. saxonica (Rabenh.). [Syn. Frustulia saxonica 

 Rabenh., 185 1; Navicula crassinervia Breb., 1852; 

 Vanheurckia rhomboides var. crassinervia V.H.]. 

 S.W.— Askern (J. M. Kirk). Cullingworth. Ogden Clough. 

 Cragg Vale, towards Blackstone Edge. 



Mid W. — Adel Bog. Whernside. Cocket Moss, near Giggles- 

 wick. Near Buckden. 



Trans. Y.N.U., 1901 (pub. July 1901). Bot. Series, Vol. 5. 



