24 BB1T1SH DESMIDIACEJL 



Length 40 /x, ; breadth 36 /x. 

 Geogr. Distribution .- -Germany. 



The illustration 011 PL C (fig. 10) is copied from one of 

 Sclimidle's original figures. We Lave seen nothing exactly 

 like it from tLe BritisL Islands, although we Lave met with a 

 Gosmarium from Surrey which must be regarded as a form 

 of it. 



Forma. (PL C, fig. 11). 



Semicells slightly trapeziform, granules somewhat more 

 numerous; in the vertical view with a very slight granulated 

 protuberance at the middle on each side. Length 42^; 

 breadth 38 ^; breadth of isthmus 12 JJL ; thickness 23 /LI. 



ENGLAND. In a mill-pond E. of Chapel Wood in 8.E. 

 ^Surrey ! 



235. Cosmarium Broomei Thwaites. 

 (PL C, fig. 12.) 



Cosmarium Broomei Thwaites in K-alfs' Brit. Desm. 1848, p. 103, t. 16, 

 f. 6 ; Arch, in Pritch. Infus. 1861, p. 734, t. 1, f. 7 ; Kabenh. Flor. 

 Europ. Alg. Ill, 1868, p. 171 ; Lund. Desm. Suec. 1871, p. 29; Nordst. 

 Desm. Ital. 1876, p. 41 ; Kirchn. Alg. Schles. 1878, p. 154 : r Wolle, 

 Desm. U. S. 1884, p. 86, t. 17, f . 6, 7 ; Cooke, Brit. Desm. 1887, p. 109, 

 t, 40, f. 1 ; Hansg. Prodr. Algenfl. Bohm. 1888, p. 251 ; De Toni, Syll. 

 Alg. 1889, p. 1026 ; West, Alg. N. Yorks. 1889, p. 292 ; Alg. N. Wales, 

 1890, p. 290 ; Alg. W. Ireland, 1892, p. 156 ; Alg. Engl. Lake Distr. 

 1892, p. 728 ; Roy & Biss. Scott. Desm. 1894, p. 44 ; Nordst, Index Desm. 

 1896, p. 70; W. & Gr. S. West, Alg. S. England, 1897, p. 490; Alga-fl. 

 Yorks. 1900, p. 88. 



Ursinella Broomei Kuntze, Eevis. gen. jDlant. 1891, p. 924. 



Cells rather small, almost quadrate, about as long- 

 as broad, very deeply constricted, sinus narrowly 

 linear with a slightly dilated extremity ; semicells 

 oblong-rectangular or rectangular-trapeziform, with the 

 angles slightly rounded, sides convex and sometimes 

 slightly convergent upwards, apex straight or faintly 

 retuse. Side view of semicell subcircular-depressed. 

 Vertical view narrowly elliptic, with a conspicuous 

 rounded inflation at the middle on each side. Cell- 

 wall densely and finely granulate, granules quite small 

 and disposed in close vertical series, about -30-34 

 showing at the margin of a semicell. Chloroplasts 

 axile, with two pyrenoids in each semicell. 



Zygospore unknown. 



