16 12 Proceedings of the Royal Irish Academy. 



Closterium Jenneri Ealfs.— C, M, VL, CI, W; Cr, 84 X 11-1 2/*. 



var. HIBERNICUM, var. nov. — Var. cellulis longioribus 



angustioribusque quam in forma typica, et minus curvatis. 



Long, inter apices 116/*, lat. 11/*, lat. prope apices, 4-5/;, 



1 20° of arc. W. 



juncidum Ealfs.— W, 110x9/*, 206x10/*, and 165x8/ t from different 



gatherings ; D, 268 x 8/*. 



var. elongatum Boy & Biss. — A little shorter than E. & B.'s 



variety, 342 x 12/*. 

 var. brevior Eoy. — 191 X 14/i. 

 Kuetzingii Breb. — L, abundant in several places, 347 X 17/*; SL, abundant 



in the plankton, average size 417 X 17/<. 

 Leibleinii Kiitz. — C, "W; L, 157x23/*, 135° of arc; D. In one pool in 

 Clare Island among Utricularia minor and Batrachospermwm vagum, 

 a small very arcuate form occurred without ventral inflation, 

 101 x 17-5 M , 170° of arc. 



var. OCCIDENTALE var. nov. — Var. cum parte mediana marginis 

 interioris subrecta, id est, cellula sine inflatione centrali, 

 146-158 x 20-6-21-7/*. L ; DL, 153-158 x 25/*, 175° of arc ; 

 W, 172 x 22/t, 140° of arc, a form with middle of inner 

 margin distinctly, though very slightly, concave; W, 

 137 X 18-3/j, 138° of arc ; D. 

 *Libellula Focke. — W. 



var. interruptum W. & G. S. West. — M. 

 lineatum Ehrenb. — C, a small form, 356 x 18 - 7/t, 40° of arc : from another 

 place, large forms, 573x30/*, 34° of arc ; M, 45-47° of arc ; W, a small 

 form 334xl6/i, 40° of arc. 



Forma brevior, striis delicatissimis. A shorter form with 

 pale yellowish-brown cell-wall. I ; M, 435 x 32/i, 45-47° of arc. 

 Lunula (Mull.) Nitzsch.— C, B, L, I, W; D, 657x116-6/*; SL, 557x85/*. 



(PL 2, fig. 15 (form of poles)). 

 moniliferum (Bory) Ehrenb. — W; L, 269x43/*, 84° of arc; C, large much 



curved forms, 378-390x63-66/*, 140° of arc. 

 parvulum Nag. — C, in one locality small forms 90 x 12/*, 132° of arc : in 

 another place, 132 x 11/*, 120° of arc ; M, IT; L, 125 x 13'6/i ; W, D ; I, 

 . various forms, some 141-145x12-5/1, 122° of arc, near apices 4-5/*; K. 

 var. angustum W. & G. S. West.— C, 91-101 x 7-8/*, 125° of 

 arc ; I, 120° of arc; C. 

 praelongum Breb., f. brevior West. — C, 360 x 16/* : from another 

 locality 220 x 13/i : none of the examples had as long a recurved 

 apex as is usually figured. 



