Clare Island Survey — Fresh-water Algae. 16 13 



Closterium pronum Breb.— W; C, 348-380 x 10-5-11,*. 



f. BREVIUS f. nova. — Cellulis semper distincte brevioribus, 

 222-250 x 8-4-9**. C. 

 pritchardianum Arch. — D, 462 x 30**, 358 x 30-5,*, 343 x 30,* ; C, large 



forms, 495 x 51,*. 

 Pseudodianae Koy.— M ; C, 203 x 14,*; CI, 193 x 12-5, ( ; W, 164 x 12,*, 

 98° of arc : also a smaller form 155 x lit*, 84° of arc. A small form 

 was seen from Clare Island, 130 x 9'6,(. 

 Ralfsii Breb.— L, 382-384 x 38-39,* ; C, 251 x 42/*, a short form. 



var. hybridum Babenh. — W, 316-384/*, average breadth 32,< ; 

 Cr, 390 x 28yw. 

 rostratum Ehrenb.— L, AS, M, D ; C, 330 x 25/*, 343 x 26-5,,. 



var. brevirostratum West. — M, L ; C, 248 x 20/* average. 

 setaceum Ehrenb. — I, CI ; B, 1 1-12** broad; Cr, 320 x 8 - 5**. 

 striolatum Ehrenb. — W, 253 x 40**, 3b° of arc; L, very variable, short 



forms 228 x 38,*. 

 subulatum (Kiitz.) Breb. — C, 215 x 10/*. 

 *tumidum Johnson. — C, 106 x 17'6/t, a form with the ventral margin 



almost straight in the middle part. 

 Toxon West.— C ; W, 206 x 10,*. 



var. VALIDUM var. nov. — Var. cellulis duplo crassioribus quam 

 in forma typiea, 250-260 x 17-5-20**. C. (PI. 1, fig. 6.) 

 turgidum Ehrenb. — C, W. 



Ulna Focke. — D, 410 x 15**, breadth near apices 11**; C, various lengths, 

 225, 275, 285, 300, 310, 432-5, by 15-16-5** in breadth; CP, 

 295 x 22**. 

 Venus Kiitz— C, B; W, 55x6-6/*, 165° of arc; M, 80x9-8/*, 138° 

 of arc. 

 Docidium baculum Breb. — C, W. 



Pleurotaenium coronatum (Breb.) Rabenh. — IT; C, up to 464** long and 

 38/* wide. 



var. fluctuatum West. — SL, 575 x 54**, apex 50,*. 

 Ehrenbergii (Breb. ) De Bary. — M, average size 448 x 24,* at middle ; VL, 

 IT, L, W, CI; C, 319x27-5,* (just above the base of semicell) > 

 Cr, 393 X 40**, specimens up to 455** long, 

 var. granulatum Ralfs. — Cr, 240 x 17/t. 

 Trabecula (Ehrenb.) Nag.— W. 



f. clavata (Kiitz.) W.& G. S. West.— W; C, 353x33-5/*. 

 var. rectissimum W. & G. S. West. — C, in Creggan Lough, a 

 form with practically parallel sides, 418 x 20/*. 



