17$ m.MTISIT DKSMlDIACI'.l'. 



their diameter, moderately and regularly curved, outer 

 margin 4-Y -('() of arc, inner margin not tumid, gradu- 

 ally attenuated to the apices, which are acute; cell- 

 wall smootli and colourless; chloroplasts \vitli four or 

 live small pyrenoids in a central series; terminal 

 vacuoles with several small moving granules. 



Zvgospore oblong-rectangular, sides concave or 

 slightly convex, ends concave, angles produced into 

 iiiamillate or conical projections ; from the side 1 vie\v 

 the zygospore is elliptical. 



Length 132-146 /x; breadth 3'8-6/x; length of 

 /vgospore 23-40 /x ; breadth of zygospore 12-'27/u. 



ENGLAND. Cumberland ! Westmoreland ! (Bissett). 

 W. (with zygosp.), N., and E. Yorks ! Lancashire ! 

 (lull/*). Essex! Oxford (with zygosp.) ! Cam- 

 bridge! Warwick (117/7*). Middlesex! Surrev ! 

 Sussex ( K.ilJ's). Hants! (7,V//^//). Cornwall! (Rolfs). 



WALES. General ! 



SCOTLAND.- Common!; zygosp. from Aberdeen and 

 Kincardine (//"// tj' 7//'x.s-r/7). Harris and Lewis, Outer 

 Hebrides ! Shetlands! 



I i.'i'LAND. General! Also in plankton of Lough 

 Xeagh ! 



Geogr. l)ixti'il>nti<n>. France. Germany. Switzer- 

 land. Austria and Galicia. Hungary. Norway. 

 Sweden. Denmark. N. and S. Russia. Faeroes. 

 Nova. Zembla. Spitzbergen. Greenland. Central 

 China. India. Siam. Sumatra. Java. Australia. 

 New Zealand. E. Africa. United States. 



This is one of the most abundant of the sni.-dl SJKMMCS of 

 Clofiterium, ;md with tlu^ exception of ('I. parvulum is the (me 

 most ol'ton met with in the conjugated state. 



Var. Linea (Forty) West & G. S. West. (Fl. XXI 1 1, 



fig. 15.) 



)) Linea Forty, Ivloinst. Lobensf. 1S52, p. 20(i, t. 1(5. f. 20; Arch. 

 in <,)u;iH, .Toiirn. Mi'cr. Sri. ISfili, ]>. 71 ; Ifnlicnl]. Plor. Euro]). Al.t-ar. III. 

 isiis. ]>. i:',.) : |)r r |',ni, Syll. A]--. ISS'.I, p. S5 I ; West, Al\ \V. In'land. 

 IS'.iL', p. 125; Eoy ^ Hiss. Scott. I>.-SIM. 1S'.K ]>. 2l'i ; Nordst. In. lex 

 Desm. ism;, ]( . ir.s ; \v,. s l X G. S. West, Al-j. S. Kn^l.-ui.l, is.)7, p. ! 



