Clare Island Survey — Fresh- water Algae. 16 11 



Closterium Archerianum Cleve.— L, I, W ; C, a form 285 X 21ft, not more than 

 110° of arc. 

 attenuatum Ehrenb.— W, 597 x 40/* ; M. 

 calosporum Wittr.— C, CI ; L, 148 x 11'6/u, 114° of arc. 

 Cornu Ehrenb.— C, LG, W; L, 148 x 6-3//. 



var. ARCUM var. nov. — Var. cellulis curvatioribus usque 85° arci, 

 subparallelibus solum circa medium, 138 X 8'5. LG. 

 costatum Corda. — C, average size 355 X 52/*, 80° of arc : in one place the 



examples were rather narrow, 340x40/*; IT, CI, W. 

 Cynthia De Not. — W, 156 X 16/* average, 124° of arc; M. 

 Dianae Ehrenb.— C ; M, 250x26-5/*, 128 D of arc; IT, L, LG AS; CI, 

 285 x 29 - l/* ; D, VL, Cr ; I, some minor forms also from this locality, 

 163 X 14*5/*. 



var. arcuatum (Breb.) Eabenh. — C, between apices 128 x 16-5/*, 

 others 162-166 x 18, 133° of arc, a form approaching 

 type, but shorter: another gathering, 201-224x19-21/*; 

 CI, 168x21-6/*, 134° of arc; W, 137x18-3/*; L, 

 120x16-6/*, 150° of arc. 

 didymotocum Corda. — C; M, 422-5x47-5/*, 425x48/*, 428x46/*, 

 345x42-5/*, 375x45/*, breadth near apices 16-20/*, breadth at 

 20/* from apex 25-28/*, 30-37° of arc ; W. 

 *eboracense Turn., var. ACHILLENSE nov. var. — Var. cellulis semper 

 majoribus quam in forma typica, margiue ventrali leviter sed 

 distincte tumido ad partem mediam. D ; S, 262 x 61/* (the last 

 measurement was the most constant, 270x69/*, 257 x 61/*, 

 255 x 57-5/*, 290 X 63/*, 287 X 64/*). (PI. 1, tig. 13, PL 2. tig. 16 (poles).) 

 Ehrenbergii Menegh. — D, 353 x 56/* ; C, 348 X 73/* ; from a pool 

 on Croaghmore a large number of examples were measured : they 

 varied as follows: — 353-743/* long by 56-106/*. wide; S, IT, 

 I, AS, W ; L, short forms, 254 X 66/*. 

 gracile Breb. — L, W ; C, average size 172 X 6 - 6/*. 



var. tenue (Lemm.) W. & G. S. West.— W ; M, 74x3-3; 

 S. W.of D, 82x4/*. 

 incurvum Breb.— CI, 52 x lOju, 185° of arc ; L, 49 x 9-7/*, 61 x 9-6^, 



50x10/*. 

 intermedium Ealfs.— C, 260x22-5/*, 224 X 22 M , 294x21-5/*, 33-36° 

 of arc : from another place, 250-260 X 17"5 - 20/*, 33° of arc ; 

 M, L, W ; D, 224 x 16^ ; Cn, some peculiar small forms, 188-228 x 

 19-19-5/*. 



var. hibernicum West. — W. 

 B2 



