134 



MES. A. WEBEE-YAN BOSSE ON THE 



a segment remains undivided : its contents, balled together, look like a large drop of oil 

 and have a reddisli-brown colour. The first segment succeeding this undivided cell may 

 show a division into a central and pericentral cells, the next is undivided, and the 

 ultimate one has usually the shape of a spine. Sometimes the top of a branch is 

 crowned by a simple or ramified monosiphonous filament. I could find no explanation 

 for this difi^erence in development ; the monosiphonous filaments are not trichoblasts, 

 nor could any trace of^these organs be detected. The large undivided cell, with the cells 

 above it,*fall off after a shorter or longer period, and the branch that carried them is 

 blunt in consequence. 



Eig. 1. 



Schematic figure of apex of Ampliis- 

 hetema indica, showing the sym- 

 podial growth of main axis and the 

 monopodial growth of the displaced 

 shoots. After 6 segments shoot I 

 is piished aside by its first branch, 

 shoot II is also displaced after 

 6 segments by its first branch, and 

 the other shoots follow in like 



manner. 



The displaced shoots 

 carry side-branches at every second 

 segment. 



The axes have in each segment a central and six pericentral cell 

 side-branches this number may sink to four, but as a rule it is six. 



i ; in the last-formed 

 The pericentral cells, 



in common with those of Endosiphonia and Melanothamnus , cut off to the outside cells 

 quite as long as themselves ; and this may be repeated several times. In the branches 

 the cells on the dorsal side are a little longer than those on the ventral, but this difference 

 disappears with subsequent growth. The whole central strand is surrounded by a rather 

 thick layer of parenchymatous cells. The peripheral cells are of equal size and elongated 

 longitudinally, not radially as in Ifelanothammis. Though the cortical layer is pretty 



i' 



