COSMA1UUM. 169 



granules arranged in approximately vertical and horizontal 

 series across the surface of the semicells. The vertical 

 arrangement is generally more evident than the horizontal, 

 the latter being at times replaced by oblique series. The 

 granules sometimes exhibit a variation in relative size, 

 especially in the centre of the semicells,, and the large ones 

 are not infrequently duplicated. The disposition of the 

 granules in the vertical view is also somewhat variable. 



Var. pumilum Lund. (PL LXXX, figs. 20, 21.) 



C. orthostichum Lund. var. pumilum Lund. Desni. Suec. 1871, p. 25, t. 2, 

 f. 10; Boldt, Siber. Chlorophy. 1885, p. 108; West, Alg. Engl. Lake 

 Distr. 1892, p. 727 ; Roy & Biss. Scott. Besrn. 1894, p. 170. 



Smaller than the typical form, semicells oblong- 

 elliptic, granules disposed in 6 vertical and 3 horizontal 

 series. 



Length 21 '5-25 ju; breadth 20^; breadth of isth- 

 mus 5-8 /LI ; thickness 12*5-14 /t. 



ENGLAND. Borrowdale, Cumberland! Helvellvn. 



i/ 



Westmoreland ! 



SCOTLAND.- -Slewdrum, Forest of Birse, Dawin, Dal- 

 bao-ie, and Glen Clunie, Aberdeen ; Kerloch and 

 Bishop's Dam, Kincardine; Glen Clova, Forfar; near 

 Kingshouse, Argyll (Roi/ fy Bissett). Spittal of Glen 

 Shee, Perth ! Rhiconich, Sutherland ! 



Geogr. Distribution.- -GaUda in Austria. Norway. 

 Sweden. 



Var. compactum var. nov. (PL LXXX, fig. 22.) 



Smaller than the typical form, constriction deeper, 

 sinus more narrowly linear, semicells oblong-elliptic ; 

 granules in 9 vertical and 3 or 4 horizontal series, 

 vertical series upwardly divaricating, granules in the 

 centre of the semicells larger than those near the sides. 



Length 22 ^ ; breadth 22 /LI ; breadth of isthmus 6 ^ ; 

 thickness 11 /u. 



SCOTLAND. Harris, Outer Hebrides ! 



This variety differs from var. pumilum in the narrower sinus, 

 in the more numerous granules, and in their unequal size. 



