384 DESMIDE^. 



9. EUASTRUM SPINOSUM Balfs. 



Plate XCI. Fig. 9. 



Char. Frond minute, somewhat oval, compressed, rather better 



than twice as long as broad. Segments twice emarginate 



at the side. Angles often spinous, especially the distal 



ones. 

 Euastrum spinosum Ralfs, in Annals, vol. xiv. p. 192. pi. 



vii. fig. 6. ; Jenner, Flor. Tunbridge Wells^ p. 198. 

 Hah. Cheshunt : A. H, H. Barmouth : Rev. T. Salwey. 



Mayfield ; Rustliall Common ; Piltdown Common ; 



Chiltington Common ; and Rackham, near Pulborougli ; 



Dolgelly ; Penzance : Mr. Ralfs. 



A distinct thougli variable little species, and one by no 

 means uncommon. 



10. Euastrum binale Ralfs. 

 Plate XCI. Figs. 4, 5. 



Char. Frond about twice as long as broad. Segments con- 

 cave or truncate, at the end not projecting beyond the acute 

 angles. 

 a " Segments inflated at the base, the notch broad, forming 



a concavity between the angles.^'' 

 /3 truncatum. — " YYon^s quadrilateral ; the end truncate, 

 acute at the angles, loith a small triangular notch in 

 the middle ; " segments laterally tioice crenate. 

 Heterocarpella biiialis Turp., Kiitzing, Synops. Diatom, p. 

 70. Cosmarium binale Menegh., Syn. Desmid. p. 221.; 

 Ralfs, in loc. cit. ; Jenner, in loc. cit., p. 198. 

 Hab. Mayfield ; Piltdown Common, and bog near Cross 

 in Hand : Mr. Jenner. Dolgelly ; Penzance : 3Ir. 

 Ralfs. 



The variety /3 may prove to be distinct. 



