16 8 Proceedings of the Royal Irish Academy. 



Zygnejna pectinatum Ag. — C, vegetative eells 35^i broad, 92/tt long. 



leiospermum De Bary.— 0, breadth 18-19^, 2-3 times longer, zygosp. 

 25 x 30 (-oS)n ; S. W. of Dugort, 16-20 M broad, 32-48 (rarely 

 52)n long, zygospores mostly spherical (sometimes ellipsoid), 

 24-27/a, mixed among sterile Spirogyra. (Plate I, fig. 3 ; Plate II, 

 fig. 23.) 

 *Vaucherii Ag. — AS. 



var. subtile Eabenh. — D, cell. 13--15m lat., 3-4-plo longioribus, 

 The zygospores were as broad as the cells and sometimes 

 a little broader, distending them laterally, usually 1 1 times 

 as long as broad. 

 *parvulum (Kiitz.) Cooke. — C. 

 Spirogyra condensata (Vauch.) Kiitz. — C, lat. fil. 35-40/t, lat. zygosp. 

 31-37^ ; W, lat. fil. 31-5-33-5/j, 48-64^ long, zygosp. 31-32 

 x 42-46/u ; S, a form with sub-spherical zygospores, lat. fil. 

 34-41 - 5ju, zygosp. 36-39ju lat. 

 *flavescens (Hass.) Eabenh. — C, VL. 

 *insignis (Hass.) Kiitz. — C, lat. cell. 24-32/u., 3-6-plo longioribus, 



zygosp. 31-32// x 86-90ju. 

 longata (Vauch.) Kiitz. — L ; W, lat. cell. 23-27, circa 3-plo longioribus, 



zygosp. 28-32«, lat. usque 56ju long. 

 porticalis (Vauch.) Oleve. — U, lat. cell. 36-43/t ; W, lat. cell. 42-52 - 5^, 



2-3-plo longioribus, zygosp. 35-42 X 52-59//. 

 *quadrata (Hass.) Petit. — C, lat. fil. 19-22/*, saepe 12-16-plo longioribus, 



zygosp. 33-35 x 60-85/*; L, lat. cell, usque 31/x; CP, D. 

 *Weberi Kiitz.— VL. 

 tenuissima Hass. — D; 0, sterile cells. 8 - 5-ll/i broad, 10 to 13 times as 



long, 

 nitida (Dillw.) Link. — D, cells average 108// long x 72// broad, 

 varians (Hass.) Kiitz. — D, cells usually 1 5 to 2 times longer than broad, 

 28-32// wide, inflated on conjugating side, zygospores broadly 

 elliptic to roundish, 28-31// broad. 



Fam. Desmidiaceae. 



'Gonatozygon Brebissonii De Bary.— W ; L, forma 83 x 8'5-/i. 



var. laeve W. & G. S. West,— C, 128-9 x 8'5-9ju, faintly 



punctate under high power, 

 var. minutum W. & G. S. West.— M, 65 x 5'8/t; Cr, 95 x 5-6/.. 

 Kinahani (Arch.) Eabenh.— S, 343 x 14,, ; D, 250-256 x 152/< ; near 



Slievemore, a small form, 152 x 10//. 

 mojiotaenium De Bary.— W, Ac; C, small forms, 132 x 8-5ju. 



