156 BRITISH DESMIDIACEJE. 



We give a figure of a rather peculiar specimen (PI. LX, 

 fig. 4) in which the chloroplasts were neither axile nor 

 parietal, but in an intermediate condition. In the shorter 

 semicell the chloroplasts suggest a parietal disposition, whereas 

 in the longer semicell there is an axile disposition. The 

 external features of this specimen are also more in agreement 

 with those of C. Cucumis. 



16. Cosmarium microsphinctum Norclst. 

 (PL LX, figs. 5-8.) 



Cosmarium microsphinctum Nordst. Desni. Ital. 1876, p. 33, t. 12, f. 9 ; 



"VVolle, Freshw. Alg. U.S. 1887, t. 60, f. 20, 21 ; Boldt, Desm. Gronl. 



1888, p. 11 ; De Toni, Syll. Alg. 1889, p. 1005 ; West, Alg. Eng. Lake 



Distr. 1892, p. 724, t. 9, f. 32 ; Lutkem. Desm. Attersees, 1893, p. 551 ; 



Eoy & Biss. Scott. Desm. 1894, p. 168; Borg. Freshw. Alg Ostgron- 



land, 1894, p. 16, t. 1, f . 6 ; Nordst. Index Desm. 1896, p. 170 ; West 



& G. S. West, Alga-fl. Yorks. 1900, p. 70. 



Ursinella microsphincta Kuntze, Eevis. gen. plant, 1891, p. 925. 

 Dysphinctium microsiihinctum (Nordst.) Schmidle, Alg. Sumatra, 1895, 



p. 302. 



Cells small, elliptic, about 1^ times longer than 

 broad, moderately constricted, sinus uniformly narrow 

 and linear ; semicells semi- elliptic, sides convex, gradu- 

 ally converging from an almost straight base to a 

 rounded apex, basal angles subrectangular. Side 

 view of semicell ovate. Vertical view rhomboid- 

 elliptic, poles very slightly produced, ratio of axes 

 about 1 : 1*38. Cell-wall very finely punctate. Chloro- 

 plasts axile, each with one pyrenoid. 



Zygospore globose, furnished with processes arising 

 from broad bases ; apices of processes bifurcate or tri- 

 furcate. 



Length 86-39' 5 ju; breadth 25-27^; breadth of 

 isthmus 14*5-18 M; thickness 18-20^; cliam. zygosp. 

 without spines 20^, with spines 5-4 /u. 



ENGLAND.- -Heseltine Grhvll, Penyghent, and near 

 Ilkley, W. Yorks ! Mickle Fell, N. Yorks ! 



SCOTLAND. Ardtannes near Inverurie, Craigendinnie 

 near Aboyne, and Presswhin in Cromar, Aberdeen 

 (Roy $ BisseU). 



Geoc/r. Distribution.- France. Germany (var.). 

 Austria and Gralicia. Italy. Faeroes. Greenland. 

 Xova Zembla. Franz Joseph Land. United States. 



