318 FRESHWATER ALG^ OF LISMORE DISTRICT, 



in free cells not flat and incrassate but strongly arcuate and 

 thin-walled as in loose cells of Mougeotia. This is most unusual 

 in Gonatozygon^ and is probably the result of rapidly repeated 

 division. 



GoNATOZYGON Brebissonii var. MiNUTUM W. & G. S. West. 

 (Pl.xli., f.2.) 



Long. 65, lat. 4, ap. 3 /x, 



Lismore (261). 



Cf. W. k G. S. West, Br. Desm., i., p.33, PI. i., f.15. The 

 type also noted. PI. i., f.l6 of the Monograph should be placed 

 under var. Kjellmaniii {WiWe) Rac; (Gon. Kjellmanni Wille, I.e.). 



Genus P e n i u m Breb. 

 Pen. margaritaceum var. pulverulkntum, n.var. (PI. xli., f.3.) 



Forma puncta-granulis minutissimis sparsis nee in seriebus 

 ordinatis ornata. 



Long. U7, lat. 21, isth. 20, subap. 18 /x. 



Lismore (185). 

 ^ The type, with small but distinct granules in longitudinal 

 series, is very rare in this country; I have seen it only once. 

 Var. iry^egulay-ius W. & G. S. West, Alg. fr. Orkneys and Shet- 

 lands, p. 14, Pl.i., f.23 (by clerical error, var. irregulare in G. S. 

 West, Alg. Yan Yean Res., p.53) has larger granules irregularly 

 disposed. In this form, on the other hand, the granules are 

 minute, indeed hardly noticeable at the edges. Membrane very 

 faintly rufescent, almost hyaline. 



Var. iNDivisuM, n.var. (PI. xli., f.4, 5.) 



Forma baud constricta, isthmo nullo, polos versus leviter 

 attenuata; lateribus planis parallelis, vel levissime arcuatis, 

 apicibus rotundatis subtruncatis ; membrana puncta-granulis 

 minutissimis sparsis ornata, dilutissime luteola vel hyalina : 

 chloroplastidibus in medio interruptis. 



Long. 74, lat. 20, ap. 17/x. 



Lismore (185). Cum priori. 



This form is the result of repeated self -division. A specimen 

 is figured with one end expanded. 



