588 Annals of the South African Museum. 



axis of the cell turns through an angle of from 90 to 135, sometimes 

 even more. As a consequence, since the anterior pole of the cell 

 will eventually become the phialoporic pole of the developing body, 

 it follows that the phialopore of the young male bundle instead of 

 lying immediately below the parent pore, as in the case of the young 

 daughter colony formed from the gonidium, is turned sideways or 

 inwards. In the photographs this is well seen in succeeding stages 

 (Plate XLII, G to L). Very occasionally developing males are found 

 with their phialopore directed outwards, but in this species this is 

 exceptional. 



A similar shifting of the polar axis of the cell has been described by 

 Zimmermann (19236, p. 289) in a number of algae. 



2. Period of Cell-division. 



Cell-division does not begin till after the birth of the parent colony, 

 and then only in some of the male initial-cells, others remaining dor- 

 mant until later. The shifting of the polar axis within the protoplast 

 is soon followed by cell-division. The first division is always longitud- 

 inal, that is, the physiological polar axis lies in the plane of division 

 which is either perpendicular or inclined at an angle to the radius 

 passing through the mother-cell (fig. 5, G ; Plate XLII, G, H, I). 

 In Plate XLII, I, the separating of the anterior ends of the two cells 

 is already evident ; the nuclei, or rather the nucleoli, of the cells 

 are visible, that in the right-hand cell particularly clear. In Plate 

 XLII, fig. H, the nucleolus of the nearer cell, the protoplasmic con- 

 nections, and the vesicle are particularly clear. 



The second division is also longitudinal, in a plane at right angles 

 to the first (fig. 5, H ; Plate XLII, J). The hollowing to form a 

 cup is more marked, though in the 4- and sometimes even in the 

 8-celled stage the curvature is sometimes very slight (Plate XLII, K). 

 The 8-celled colony here shown, however, is somewhat unusually flat. 

 In succeeding divisions the polar axes of the individual cells become 

 constantly more inclined inwards, just as in the case of the asexual 

 daughter colony. Up to the 4-celIed stage the size of the cells does 

 not differ markedly from that in the corresponding stage of division 

 of the gonidium, but from thence onwards a distinct difference begins. 

 There is some enlargement of the whole mass during division the 

 undivided mother-cell may reach 20 /JL in diameter, the hollow spheroid 

 at the end of division measures just over 40 p. in longest diameter (e.g. 

 that shown on Plate XLII, N, was 33 x 41 /z), but a great part of this 



