THE MARINE BOTANIST. 239 



Wrangelia, Frond articulated, pinnate. Tetra- 

 spores scattered in the ramuli. 



Seirospora. Frond articulated. Tetraspores in 

 bead-like strings. 



Callithamnion. Frond, at least the branches and 

 ramuli articulated, mostly pinnated. Favellse 

 sessile. Tetraspores sessile or stalked, scat- 

 tered. 



PTILOTA. 



Name meaning pinnated^ in allusion to the finely pinnate 

 frond. 



Frond inarticulate, linear, compressed or flat, 

 distichous, pectinato-pinnate ; the pinnules some- 

 times articulate. Fructification : 1. roundish, 

 clustered y^y^//^ surrounded by an involucre of 

 short ramuli ) 2. tetraspores attached to or im- 

 mersed in the ultimate pinnules." 



