384 DESMIDE^. 



9. EUASTRUM SPINOSUM Ralfs, 



Plate XCI. Fig. 9. 



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

 than tivice as long as hroad. 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. 



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

 Mayfield ; Rusthall Common ; Piltdown Common ; 

 Chiltington Common ; and Rackham, near Pulborough ; 

 Dolgelly ; Penzance : Mr, Ralfs. 



A distinct though variable little species, and one by no 

 means uncommon. 



10. Euastrum binale Ralfs. 



Plate XCI. Figs. 4, 5. 



Char. Frond about tivice 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.''^ 

 /S truncatum. — ^'^ Yvonds quadj-ilateral ; the end truncate, 

 acute at the angles, ivith a small triangular notch in 

 the middle ; " segments laterally twice crenate. 



Heterocarpella binalis Turp., Klitzing, 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 : Mr. 

 Ralfs. 



The variety /3 may prove to be distinct. 



