596 Annals of the South African Museum. 



11.5 p.m. Another globoid escaped, this time without visible 



distortion. 



The regular gaps left by escaped globoids are a very distinctive 

 feature of maturing male colonies (cf. Plate XX, B). 



6. Life of Globoid free in the Water Escape of Sperms. 



As the globoid escapes, its rate of movement increases greatly and 

 it moves here and there on the slide with great rapidity, rotating on 

 its axis all the time. No phototactism was detected, nor could it be 

 decided what caused change in direction. The energy used in move- 

 ment must be enormous in proportion to the size of the individual 

 cells (sperms), the cilia being much longer than the body of the sperm 

 (fig. 7, D). Probably a great part of the food-store is consumed during 

 this movement, but since the sperms contain chlorophyll, photo- 

 synthesis may continue during the free life. 



The globoid may continue moving intact for some hours or the 

 sperms may begin to escape almost at once. Apparently globoids 

 liberated into the cavity of the parent break up more rapidly than 

 those free in the water, but it is possible that in the cases observed 

 this was due to exceptional sexual activity. 



The surface of the mature globoid is divided very regularly into 

 small, more or less hexagonal areas, formed by the anterior ends of 

 the sperms, which are truncate, with the cilia inserted to one side 

 (fig. 7, A). The first sign of breaking up is seen in a blurring of the 

 outline of these divisions and a general loosening of the compact sperms. 

 Strictly speaking, the liberation of the sperms is not a process of the 

 breaking up of the globoid, but of the escape therefrom of the individual 

 sperms ; it must be remembered that the sperms are enclosed in a 

 delicate membrane, and this can be seen partly or entirely empty 

 as the sperms escape. The pore of escape is the pore of closure of 

 the inverting male bundle. The exact mechanism of escape is very 

 difficult to see, but appears to be as follows : 



The sperms draw their cilia back through the common membrane 

 and can be seen actively moving about inside it (fig. 7, B ; Plate 

 XLV, C, D). This takes place gradually, and as long as any of the 

 cilia still project they continue to move the globoid very actively, 

 and usually before all are withdrawn a number of sperms have par- 

 tially freed themselves, and in their endeavours to get quite free 

 continue moving the whole mass the globoids shown in these two 

 figures were by no means quiescent and had to be killed before they 



