116 



ERNEST WARREN. 



fig. 4, a) . It is pretty cleai- that these streaks do not neces- 

 sarily correspond to the outlines of cells, but they involve 

 several cells or portions of the same. 



Sometimes, and especially in the endoderm, in place of 

 the walls of the vacuolated cytoplasm being conspicuously 

 blackened, the pigment becomes concentrated in somewhat 

 large, irreguhirly shaped lumps wliicli subsequently lie loose 



Text-fig. 5. 



Thuiaria tubuliformis (M.-Turn.). x 1200. 



in the vacuoles, and are very opaque (text-fig. 5, a-c). As 

 a result of this degeneration, the areas form leopard-like spots 

 (PI. XII, fig. 4). 



(3) Sertularia operculata Lin. 

 PI. XII, figs. 6-8 ; text-fig. 6. 



Most of the colonies collected between th3 tide-marks on 

 the Natal coast exhibited pigment-degeneration to a greater 

 or lesser degree, but one or two small young colonies were 

 practically free from it. In a specimen received from 

 Plymouth, England, a certain amount of degeneration was 

 observable. 



In older colonies the degeneration may become excessive, 

 especially in the ectoderm of the coenosarc (PI. XII, figs 6-8), 

 and it appears to lead to the formation of actual divisions 



