ei,osTi-:i;irM. 1 l : > 



in the middle, uniformly narrowed to the apices, wliieh 

 are obtusely rounded ; cell-wall smooth and colourless; 

 chloroplasts with distinct ridges (about six in number) 

 mid with a single series of (> or 7 pyrenoids ; terminal 

 vacuoles with numerous moving granules. 



Zygospore ellipsoid and smooth, with nn outer 

 mucous, lamellose coat. 



Distance between apices (length) 222-3 70 p,; breadth 

 oo-50 p ; breadth of apices 8-11 ^. 



EN< IL.\ xi >. Cumberland ! Westmoreland (at 2,400 ft . 

 on Helvellyn) ! (l!lft). W., N., and E. Yorks! Lanca- 

 shire (Ralfo). Leicester (Boy). Lincoln! Norfolk! 

 Essex! Cambridge! Gloucester! (TiWfc). Middle- 

 sex! (I-LiMi'I). Surrey! (7.V//V). Sussex (Ralfi). 

 Kent! Hants! Devon"! Cornwall ! (7.V//V). 



WALKS. Yr Orsedd ! , Bethesda ! , Snowdon ! , and 

 Capel Curig (('<><>/,/' $ H7//.s), Carnarvonshire. Llyn 

 Coron, Anglesey ! Ffestiniog, Merioneth ! 



SCOTLAND. Caithness, Ross, Inverness !, Aberdeen ! , 

 Kincardine!, Forfar ! , Perth!, Fife (I'fnif <$ Jliwtt). 

 Shetlands ! 



IRELAND. Donegal ! Mayo ! Kerry ! Wicklow ! 

 (Arrhrr). Down! Antrim! 



Gcofjr. TfiHtrUnitlni. France. Belgium. Grermany. 

 S wit zerland . (\ alicia in Austria. Hungary and Bosnia . 

 Italy. Portugal. Norway. Sweden. Denmark. Born- 

 holm. N. and S. Russia. Poland. Faeroes. Iceland. 

 China. .Japan. Ceylon. New Zealand. Central 

 Africa. United States. Brazil. Argentina. Uruguay. 

 Patagonia. 



This species is distinguished from ('/. Leibleinii hy its lesser 

 curvature, its hrnader :uul iimrc rounded apices, and its larger 

 si/e. It differs from ('I. Khrrnliergii vn its sonie\vli;it sni;dlrr 

 size, and in the central ro\v of pyreiioids present in each 

 ehloroplast. 



24. Closterium Ehrenbergii ]\Ienegh. 

 (PI. XVII, figs. 1-k) 



Closterium Ehrenbcniii Mcm-^h. Synops. Desm. 1840, p. 232 ; Hass. Brit. 

 Freshw. Al\ 184-i, p. 369, t, 87, f . 1 ; Ealfs, Brit. Desm. 1S4S, p. 1GG, 



