51 



the one hand and a somewhat elongated shape on the 

 other. When eight oospheres are rounded off there 

 are usually two at the top, four in the middle, and 

 two at the bottom, but in the elongated oogonium 

 of Notheia there is one each at top and bottom and 

 two groups of three between. When four oospheres 

 are formed, three usually occupy the base with one 

 above, but it also happens (e.g. Sarcophycus) that the 

 protoplasm divides into three transversely and the 

 middle portion afterwards into two longitudinally. 

 In cases of two, the one is placed above the other. 



When the outer wall of the oogonium bursts, the 

 rounding of the oospheres is soon completed and they 

 are extruded together, still within the inner wall, 

 which either bursts in turn or appears to dissolve, 

 setting free the oospheres into the surrounding water. 

 In Pelvetia, however, the gelatinous wall persists 

 without apparently proving an obstacle to fertilisation. 



The antheridia occur as the terminal cells of 

 branches of much-branched hairs. They are gener- 

 ally of a longish oval form and are produced in great 

 abundance. The antherozoids have each two lateral 

 cilia emerging near the apex, and a red pigment spot. 

 In some genera they do not escape forthwith as in- 

 dividuals, but, like the oospheres, pass out of the con- 

 ceptacle enveloped within the inner wall of the parent 

 cell, while in others they are at once set free so far as 

 this membrane is concerned, but remain close together 

 in a mass until they emerge from the conceptacle. 



The paraphyses of the Fucacecc are unbranched, and 

 those near the ostiole frequently protrude. Whether 

 they guide the oospheres and antherozoids outwards, 



E 2 



