502 Annals of the South African Museum. 



have but two pyrenoids, so that perhaps they multiply with the 

 increase in size of the cell. 



There is a certain degree of resemblance between E. simplex and 

 Senn's Chlorodendron (Euglenopsis of Davis, Ann. of But., viii, 1894, 

 p. 377), since here also the colony gradually elongates by the succes- 

 sive withdrawal of the protoplast towards the upper end of the cell. 

 In Chlorodendron, however, the contracted protoplast is merely demar- 

 cated by the formation of successive septa across the mother-cell, and 

 there is no repeated rejuvenescence, as in E. simplex. It is the 

 repeated rupture of the mother-cell membranes that shows that this 

 process in our Alga is nothing else than a modification of the usual 

 mode of development in EcbaUoci/stis, in which, however, the customary 

 division of the protoplast fails to occur. 



The discovery of these two new forms shows that the dendroid type 

 is more frequent among the lower Isokontae than has hitherto been 

 supposed. A satisfactory elucidation of the affinities of all these forms 

 can, however, only be attained when the character of the swarmers is 

 fully known. 



(c) TETRASPORALES. 



(1) SPHAEROCYSTACEAE. 



Genus SPHAEROCYSTIS Chodat. 



1. Sphaerocystis schroeteri, Chodat, Etudes d. Biol, lacustre, 

 Bull. d. l'Herb. Boissier, 1897, p. 292, Tab. IX ; Alg. vert, de la 

 Suisse, Berne, 1902, p. 114, Fig. 53. 



Samples 8, 48. 



(2) TETRASPORACEAE. 



Genus APIOCYSTIS Naegeli. 



1. Apiocystis brauniana, Naegeli, Gatt. einzell. Algen, 1848, p. 67, 

 Tab. II, A, Fig. 1 (Fig. 5). 



Samples 30a, 31,33 (on Cladophora glomerata). 



Diain. colon, in media parte, 63-136 \>- ; long, colon, tot., 100-195 //, ; 

 long, stip., 22-45 /i ; lat. stip. in media parte, 20-27 /'. ; diam. cell., 

 6-10 i>. 



The above dimensions are for mature colonies ; young colonies were 

 quite frequent. The stalk was on the whole broader and longer than 



