86 BRITISH DESMIDIACE^E. 



divergent processes, which are emarginate or tri-dentate 

 at the apex ; vertical view 2-5 -radiate, lateral margins 

 strongly concave, angles produced into processes. Cell- 

 wall smooth, except for the processes, which are some- 

 times finely granulate. 



Zygospore unknown. 



Length (not including the processes) 14-17 [/. ; breadth 

 (not including the processes) ll-15(i; distance between 

 the tips of the processes 19-30 y.. 



SCOTLAND.- -Bishop's Loch and Tomachar, Aberdeen 

 (Roy & Biss.). 



Geogr. Distribution. Germany. Italy. Scandinavia. 

 United States. 



Reinsch's figures include several Staurastra which differ 

 amongst themselves in many respects, so that one almost doubts 

 that they can all belong to the same species. Unfortunately, 

 no other figures of St. franconicum have ever been published, 

 and these original ones of Reinsch are very unsatisfactory. 



104. Staurastrum inconspicuum Nordst. 

 (PL CXLI, figs. 4-7 ; PL CXLII, fig. 8.) 



Staurastnim sp. Arch, in Quart. Journ. Micr. Sci. 1855, p. 89. 



St. minutissimum Auersw. in Rab. Alg. Eur. 1863, no. 1428 (ex parte). 



St. inconspicuum Nordst. Norges Desm. 1873, p. 26, t. 1, f. 11 ; Arch, in 

 Journ. Bot. 1874, p. 91 ; Wolle, Desm. U. S. 1884, p. 125, t, 53, f. 4, 5 ; 

 Cooke, Brit, Desm. 1887, p. 153, t. 54, f . 3 ; De Toni, Syll. Alg. 1889, 

 p. 1183; Heimerl, Desm. alp. 1891, p. 606; West, Alg. W. Ireland, 

 1892, p. 178; Liitkem. Desm. Attersees, 1893, p. 565; Roy & Biss. 

 Scott, Desm. 1893, p. 21 ; West & G. S. West, Some N. Amer. Desm. 

 1896, p. 257. t, 16, f. 14 ; Alg. S. England, 1897, p. 495 ; Liitkem. Desm. 

 Millstattersees, 1900, p. 22, t. 1, f. 54 ; Comere, Desm. de France, 1901, 

 p. 154, t. 11, f. 11 ; Borg. Alg. Faeroes, 1901, p. 235, t. 8, f. 4 ; West & 

 G. S. West, Alg. N. Ireland, 1902, p. 49 ; Brit. Freshw. Phytoplankton, 

 1909, p. 203. 



St. refractum Delp. Spec. Desm. subalp. 1877, p. 138, t. 11, f. 7-9. 



St. subrefractum Lemaire, Liste Desm. Vosges, 1883, p. 23, t. 1, f. 3. 



Cells minute, about as long as broad, including the 

 processes, sinus nearly semicircular ; semicells roughly 

 quadrangular, apex slightly elevated but concave in 

 the middle; upper angles produced to form short stout 



