BY G. 1. PLAYPAIR. 829 



Genus P t e R o m o n a s Seligo. 



Pteromonas cruciata, n.sp (PI. Ivi., f.24, 25). 



Cellulfe ovales alis geiiiinatis binis cruciatim dispositis in- 

 structte; a froiite visjv (alis inclusis) ovat;i?, postice acuminat;t», 

 inai'gine inaequali aspero; a latere insequalitei' quadratse (alis 

 inclusis) anterioi-e angustatse fronte truncatse, lateribus planis, 

 postice levissime arcuatae, apice in bulla conica projiciente; a 

 vertice cruciformes, corpora I'homboideo, angulis prodlictis. 

 Meinbrana hyalina. 



Cell. long. s. alis 16-20, lat. 10-12; c. alis long. 24, lat. 18//. 



Lismore (263). 



The body is oval, with contents as in (Jhl(irnydonii)itafi, save 

 that the red spot is placed towards the hinder end. The cell is 

 furnished with two pairs of wings lying in planes which intersect 

 at right angles, making the end-view cruciform. 



Var. PULCHRA, n.var. (PI. Ivi., f.26). 



Cellulte a latere angulis alarum inferioribus truncatis et pro- 

 tractis, lateribus paullo retusis; ceteris ut in f. typica. 



Cell. c. alis long. 24, lat. fronte 12, postice 18/x. Alse long. 20/x. 



Lismore (263). 



The lower angles of one pair uf wings are truncate and pro- 

 duced, the sides somewhat retuse. A pyrenoid present, as a rule, 

 in both type and variation. 



Genus VoLVULiNA Playf . 

 VoLV. .Steinii var. lenticularis Playf., forma. 



Coenob. diam. 32-50; cell. diam. 10, inter se dist. 1/x, alt. in sect. 

 optical. 5-1 2/x. Lismore (263, 293). 



A new locality for Vohndiua. Tlie coenobium gives the im- 

 pression that the cells are the result of fragmentation of a 

 parietal chloroplast. From above, the cells are generally quadrate 

 or polyhedral, fitting into one another, the edges not more than 

 1/x apart; sometimes, however, they are circular. The cells are 

 certainly lenticular in optical section. There are 16 in tlie 

 ccenobium, arranged more or less in three layers, 4 -t- 1, 6, 4 -f- 1. 



