CATALOGUE OF PLANTS, 613 
. acutus, Meyen. 
Same habitat. 
. obtusus, Meyen. 
Same habitat. 
OPHIOCYTIUM, Neg. 
. cochleare, A. Br. 
Frequent in stagnant ponds. 
. capitatum, Wolle. 
Same habitat. 
CHARACIUM, A. Br. 
. Sessile, Herm. 
Sussex: Cranberry Pond, on alge. 
PROTOCOCCUS, Ag. 
. viridis, Ag. 
Everywhere common on the shaded side of trees, houses, 
rocks, ete. Mr. Wolle recognizes a large number of aérial and 
aquatic forms as varieties of this species. 
POLYEDRIUM, Neg. 
. trigonum, Neg. ‘ 
. gigas, Wittr. 
. enorme (Ralfs.), Rab. 
All found in ponds. 
PALMELLACE. 
DICTYOSPHAIRIUM, Neg. 
. Bhrenbergianum, Neg. 
In ponds; frequent. 
. reniforme, Bulnh. 
Same habitat; occasional. 
. Hitchcockii, Wolle. 
Morris: Frequent in Denmark and Split Rock Ponds. 
