CLoSTia'H'M. 107 



Schlcs. isys, p. i:;7; Wolle, Desm. U.S. 1884, p. 39, t. 0, f. 4, 5 ; Cook.-, 

 IJrit. D.-sni. 188t>, p. 22,1. 13, f. 8; Hans-;-. 1'r.Mlr. Al-riiil. Uuliiii. 1SSS, 

 p. 178; Do T..ni. Syll. Ali;-. ISM), p. 818; \i<>\- \ Hiss. Scott. Dcsm. 1894, 

 p. 244 ; Nordst, Index Dc-siu. 1890, p. 132; West & <i. 8. West, Ncu 

 and Int. Freshw. Alg-. 1890, p. 151,1,4, f. 47; Al^. S. En-land, 181)7, 

 p. 54 ; Alu-a-ii. Y(irks. 11MK), p. 51 ; Aly. N. Iruland, 1901', p. L'5 ; Frushw. 

 Alt;-. Cry Ion, 11)02, p. 138. 



C'l. JHiici'l inn Ji';ilt's, forma gracillima-lxvissima Rabenh. Flur. Em-op. 

 Algar. Ill, 1808, p. 127. 



C'l. ijracile forma ti'imixxhita Heimerl, JJosin. Alp. 1891, p. 591. 



Arthrodia gracilis Kuntze, Kevis. vn. plant. 1891, p. 883. 



Closti'rimii litnneticuni Lemm. Pliytoplanktoii siichsis. Tek-lic, 181)9, p. 28, 

 t. 2, f. 39-41 ; vide West & (Jr. S. West, Notes Aly. II, 19UU, p. 290. 



Cells small, slender and linear, 28-40 times longer 

 than their diameter, almost straight for more than half 

 their length, margins parallel, gradually narrowed and 

 gracefully curved towards the apices, which are obtuse ; 

 cell- wall smooth and colourless ; choroplasts sometimes 

 suljuiidulate, with 5 to 7 pyrenoids ; terminal vacuoles 

 with one to several moving granules. 



Zygospore globose, angular-globose, or subquadrate 

 with rounded angles, smooth. 



Length 130-190 /A; breadth o'4-6/x; breadth of 

 apices 1' 2-2 '4 /A; diam. zygosp. 20-25'7/x. 



ENGLAND. Cumberland ! Westmoreland ! W., X., 

 anclE. Yorks ! Lancashire! Cheshire (Ho //). Essex! 

 Cambridge ! Oxford (zygosp. from near Goring) ! 

 Middlesex ! Surrey ! Hants, (zygosp. from New 

 Forest)! Devon! Cornwall! (Marquand) ; zygosp. 

 from Penzance (Joshua). 



WALES. Fairly general ! 



SCOTLAND. Ross ! , Sutherland ! , Inverness ! , Nairn, 

 Aberdeen (with zygosp.), Kincardine, Forfar ! , Perth ! , 

 Argyll (Ho// fy Bissett). General in Outer Hebrides! 

 Orkneys ! Shetlands ! 



IRELAND. Donegal ! Mayo ! Galway ! Kerry ! 

 Dublin and Wicklow (Archer). Antrim! Down! 



Geot/r. lUxh-ilmlion. France. Germany. Austria 

 and Galicia. Hungary. Portugal. Norway. Sweden. 

 Denmark. N., Central, and S. Russia. Finland. 

 Faeroes. Iceland. Siberia. Greenland. Ceylon. Siam. 

 Sumatra. New Zealand. Australia. E. Africa. 

 United States. Brazil. Paraguay. Patagonia. 



