loS KIMTISII DMS^IIlUACJi.K. 



right angles to that containing the two angle's of the 

 opposite end. 



Distance between apices 51-81 /x ; breadth 7-10 - 5 ^ ; 

 length of zygospore 23-28*5 /x ; breadth of zygosp. 

 18-22/1. 



ENGLAND. Westmoreland ! W., N., and E. Yorks ! 

 Lancashire ! Cheshire (Ri/). Leicester (//"//). Cam- 

 bridge ! Oxford (zygosp. from near Goring) ! Essex ! 

 Surrey! Hants! Cornwall (Mari/iiaiitJ). 



WALKS. Fairly general ! 



SCOTLAND. General! (/'<>// A' />>**'//). General in 

 Outer Hebrides ! Orkneys! Shetlands ! 



/ 



IRELAND. Donegal! Galwav ! Kerry! Down! 



O e/ 



Armagh! Antrim! Lough Neagh ! Dublin and 

 Wicklow (Airher). 



<i<'o<jr. Distribution. France. Germany. Austria 

 and Galicia. Hungary. Italy. Norway. Sweden. 

 N. Russia. Faeroes. Nova Zembla. Greenland. 

 Siberia. Central China. Japan. Ceylon. Burmali. 

 Siam. New Zealand. Central Africa. Azores. United 

 States. Brazil. Patagonia. 



The curvature of Cl. Venun distinguishes it from (7. ]_>a r- 

 ru/nui, and it is invariably uf smaller dimensions. As a rule 

 the apices are slightly more attenuated than those of Cl. 

 parvulum, and there are rarely more than two pyrcnoids in 

 eacli chloroplast. 



Tlie curvature is almost the same as that of ('/. Ji'innri, 

 hut the hitter is a larger species of stouter aspect, with much 

 thicker apices. The chloroplasts and terminal vacuoles are 

 also different from those of (7. Jcinn-rl. 



Cl. Venn** luis a very characteristic /ygospore, which is a! 

 once snllicient to separate it as a well-marked species from all 

 other small,, strongly curved Closti-ria. 



20. Closterium calosporum \Vittr. 

 (IM. XVI, figs. 1-4.) 



Cloxli'i-iinii cii/asiiitnnit Wittr. Skamliiuiv. Dcsni. isiiii, ]>._:!, t. i, f. 11 ; 



Ijiunl. hcsin. Slice. 1871, p. 81 ; Cuukc, Urit. l.)t-siii. 18S(j, p. ^'7, 1. 1:5, L 



<i; Dr'l'uni, Syll. A I--. 18S1I, p. 81-2; li'>y &. Uiss. Scott, iM-sin. 18! (4, p. 



I'll-. N..nls(. hi.t.-x Desm. 1896, p. 71; West i (I. S. Wc-st, Alg. N. 



Irehuul, 1902, p. 23 ; 1'reshw. Alg. Ceylon, 1902, p. l-k>. 

 Arthrudui calospora Kxiutze, Eevis. gen. plant. 1891, p. 883. 



