('LdSTKK'lUM. 1 S'J 



and slightly dilated ; coil-wall straw-coloured, finely 

 striated, l2.")-i37 stria 1 visible across tlie cell ; chloro- 

 plasts \vith four or five pyrenoids ; terminal vacuoles 

 large, situated within the base of the apical processes, 

 and containing from twelve to fifteen moving Grannies. 



Xvo-osporo somewhat rectangular, with hollow sides, 

 angles truncate and concave. 



'Length i>4()-.V'.0/A; breadth l'. -:(I/A; breadlli of 

 apices :> '4- oju,; maximum breadth of zygospore 7 0-7 7 /z; 

 minimum breadth of /ygosp. oS-IO/x. 



EXCLAXII. Cumberland (with /ygosp.) ! Westmore- 

 land (AW/*) ; with xygnsp. ! Lancashire! 

 W. (with /ygnsp.) and N. Vorks ! Cheshire 

 Leicester (/re//). Lincolnshire! Cambridge! Warwick 

 (M7//.S-). ("Gloucester ( Hnlfx). Surrey (with zygosp.) ! 

 Sussex (lt<ilfi). Kent ! '(/,W/x). llants ! (Bennett}. 

 Devon! Cornwall (//^//x); with /y^osp. ! 



WALKS. Fairly general ! 



SCOTLAND. General! (//".// 4' 7>/xx/'/Y). Lewis, Outer 

 Hebrides! Orkneys ! Often in the freshwater plankton. 



IKKLAXP. Donegal! Gal way ! Kerry! Dublin and 

 Wicklow (A rclicr}. Antrim! 



dcoiji'. Distribution. France. Germany. Austria 

 and Galicia. Hungary. Italy. Portugal. Norway. 

 Sweden. Bornholm. Poland. N., Central, and S. 

 Russia. Finland. Faeroes. Iceland. NovaZembla. 

 Greenland. Siberia. Japan. Ceylon (form). E. 

 Africa. United States. Brazil. Ecuador. Paraguav. 



This species is o-eiieva.lly distributed nil over the British 

 Islands, and in bnu'u'y ditches and ponds it often occurs in 

 abundance. It is a stout species and is very frequently 

 obtained in the conjugated state, particularly in the south of 

 Mn^-land. The apical processes are much shorter and more 

 robust than those of (7. Kiif:;/i/</ii, and the cell-wall is more 

 finely and delicately striated. 



Yar. brevirostratum West. (PL XXVI, figs. C-8.) 



Cl. nixtrutinii var. ?-/vri.-ns/r<///jn West, Dcsin. Mass. 1SS<), p. IT. t. 1', f . '.I : 

 Nm-.lst, Index Uesni. IS'.Ki, p. 225 ; West & G. S. West. Ali?. S. En-bm.l. 

 1S ( J7, p. 482. 



