157 



Length .50-139 /*; breadth 77-1 /x ; breadth of 

 apices 2'5-5'5/x; length of zygospore 3 4-37'5 /x ; 

 breadth of zygospore 20-30/1. 



ENGLAND. Bowness, Westmoreland ! Xear Lindlt-v 

 Reservoir, Eldwick, and Ribblehead, W. Yorks ! 



WALES. Capel Cnrig, Carnarvonshire ! 



SCOTLAND. Near Alford, Aberdeen (//"// <.y IH.wtf). 



(icixjr. I )/xtril/ti<>u. Norway. NovaZembla. Siani. 

 Celebes. Samoa. United States. Brazil. Paraguay. 

 Patagonia. 



This species is distinguished from G'Z. Conut, Ehrenb. by the 

 shorter and broader cells, with a tumid ventral (or inner) 



34. Closterium Cornu Ehrenb. 

 (PI. XX, figs. 1-5.) 



Closterium Cornu Ehrenb. 1830; Entwick. Lebends. d. Infus. 1832, p. 67; 



Infus. p. 94, t. 6, f. v ; Menegh. Synops. Desm. 1840, p. 233 ; Hass. Brit. 



Freshw. Alg. 1845, p. 372, t. 88, f. 2; Kali's, Brit. Desm. 1848, p. 176, 



t. 30, f. 6/, fj; Breb. Liste Desm. 1856, p. 154; Arch, in Pritch. Infus. 



1861, p. 750; Eabenh. Flor. Europ. Algar. Ill, 186N, p. 137; Kirchn. 



Alg. Schles. 1878, p. 140; ('nuke, Brit. Desm. 1886, p. 35, t. 12, f. 4 ; 



Hansg. Prodr. Algenfl. Bohm. 1888, p. 181; Do Toni, Syll. Alg. issit, 



p. 835 ; West, Alg. aq. clulc. Lusitan. 1892, p. 1500; Eoy'A: Biss. Scott, 



Desm. 1894, p. 244; Nordst. Index Desm. 1896, p. 82; West & G. S. 



West, Alg. S. England, 1897, p. 482; Alga-fl. Yorks. 1900, p. 53 : Alg. 



N. Ireland, 1902, p. 25, t, 2, f. 4, 5. 



Cl. tame Kiitz. Syn. Diat, 1834, p. 595, t. 18, f. 7s (p). 



Stauroceras Cornu Grun. Desm. u. Pediast. osterreich. Moore, 1858, p. 497. 

 Closterium pronum Breb. c Cornu Klebs, Desm. Ostpreuss. 1879, p 19, t 2, 



f. 136. 



Arthr<t<lit( Cornu Kunt/.e, llevis. gen. plant. 1891, p. 883. 

 Closterium Cornu var. S/IMKC/OV West & G. S. West, Chlorophy. Koh 



Chang, 1901, p. 166, t, 2, figs. 6, 7. 



Cells small, 1(3-20 times longer than their diameter, 

 slightly curved, outer margin 34-40 of arc, inner 

 margin slightly concave and usually straight in the 

 median part, margins parallel until near the extremities, 

 which are gradually attenuated ; apices narrow, rounded 

 or rounded-truncate ; cell-wall smooth and colourless ; 

 chloroplasts with 3-5 pyrenoids ; terminal vacuoles 

 with one oblong moving granule. 



Zygospore subquadrate or rectangular, sides straight, 



