164 BRITISH DESMIDIACE2E. 



Var. strigosum Nordst. (PL LX, figs. 26, 27.) 



C. asphserosporuni Nordst. var. strigosum Nordst. in Wittr., Nordst. et 

 Lagerh. Alg. Exsic. 1896, No. 1264 ; Bot. Notiser 1897, p. 86, cum fig. 

 xylogr. ; West & G. S. West, Alg. S. England, 1897, p. 486. 



Cells witli a narrower isthmus and consequently with 

 a deeper sinus, apices flatter; vertical view elliptic 

 with no trace of median inflation. 



Length 10-11 /A; breadth 8-10 /x, ; breadth of 

 isthmus 3*5 /z, ; thickness 5 p. 



ENGLAND. Puttenham Common, Surrey ! 



Geogr. Distribution. Sweden. 



This variety differs from C. bioculatum Breb. in its smaller 

 size, its more open sinus, and its broad, truncate apices. From 

 C. bioculatum var. hians it is distinguished by its smaller 

 size, its straighter apices, its less-rounded lateral angles, and 

 its smooth cell-wall. 



23. Cosmarium inconspicuum West & G-. S. West. 



(PL LXI, figs. 1, 2.) 



Cosmarium inconspicuum West & G. S. West, New and Int. Freshw. Alg. 

 1896, p. 154, t. 4, f. 45 ; Alg. S. England, 1897, p. 486 ; Alga-fl. Yorks. 

 1900, p. 74 ; Alg. N. Ireland, 1902, p. 34. 



Cells minute, about 1-g- times longer than broad, 

 moderately constricted, sinus open, subrectangular, 

 with a rounded apex; semicells transversely elliptic, 

 apices broadly convex, almost subtruncate. Side view 

 of semicell subcircular. Vertical view elliptic, ratio of 

 axes about 1 : 1*7. Cell-wall smooth and colourless. 

 Chloroplasts axile, each with one pyrenoid. 



Zygospore ovoid, with a smooth and colourless wall. 



Length 13-5-14-6 /u; breadth 9*5-12 ,u; breadth of 

 isthmus 4*8-6*5 ju; thickness 7-7*6 ft; cliam. zygosp. 

 1 4-5-17 fi. 



ENGLAND. Bog two miles S. of Clapham, W. Yorks ! 

 Mitcham Common, Surrey (with zygospores) ! Treme- 

 thick Moor, Cornwall ! 



IRELAND. Grlendoan and Lough G-artan, Donegal ! 



This species is a near ally of C. tenue Arch., C. tinctum 

 Ralfs, and C. minutissimum Arch., all of which have smooth 



