380 DESMIDEJiJ. 



zu Berlin, 1833 (1832), p. 247.; Ehr. Infus. p. 162. 

 pi. xii. fig. 5.; Kalfs, in Annals, vol. xlv. pi. vi. fig. 3.; 

 Jenner, in Fl. Tunb. Wells, p. 198. ; Pritch. Infus. 

 p. 196. fig. 125. Cosmarium verrucosum Menegh., 

 Synops. Desmid. in Linn^ea, 1840, p. 222. 

 Hah. Chesliunt : A. H. H. Rusthall Common, and Ash- 

 down Forest : Mj\ Jenner. Penzance : Mr. Ralfs. 



Tills is a very distinct species and the only British one of 

 the genus Avhich has a dentated frond. 



2. EUASTRUM OBLONGUM Ralfs. 



Plate XCI. Fig. 1. 



Char. Frond large, smooth, ohlong, oval, dotted, three or four 

 times longer than broad. Segments in front view Jive- 

 lobed, semi- oval ; lobes hroad, suhcuneate, emarginate : in 

 lateral y'lcvf pyraiyiidal, furjiished ^cith six tubercles each. 

 Euastrum pecten, Abhandl. der Akademie d. Wlssensch. zu 

 Berlin, 1831, p. 82. Euastrum pecten Ehr,, Infus. p. 162. 

 pi. xii. fig. 4. ; Pritch. Infus. j). 196. Echinella oblonga 

 Grev., in Hook. Br. Fl. vol. ii. p. 398. (1830). Cos- 

 marium ohlongum Menegh., 1. c. p. 221. Eutomia oblonga 

 Harv., Man. Br. Al. p. 188. ; Ralfs, in Annals, vol. xlv. 

 p. 189. pi. V. fig. 4. ; Jenner, in Fl. Tunbrldge Wells, 

 p. 198. 



Hab. Bogs at Fisher's Castle ; Rusthall Common ; War- 

 bleton, &c., Beckley : 3Ir. Jenner. Penzance, Dolgelly, 

 and Caernarvon : Mr. Ralfs. Aberdeen : Dr. Dickie. 

 High Beech: A. H. H. 



This is the finest species of the genus, and a beautiful 

 microscopic object, as are most of the species of this genus. 



3. Euastrum Pelta Ralfs. 



Plate XCI. Fig. 3. 



Char. Frond three times as long as broad, subquadrilateral. 



