( /Jl ) 



to the young until it has grown to a size much larger than that of its 

 predecessor, and from which it is at length separated by the constant 

 lashing of the waves. This old frond is separated from the new one 

 by a narrow constriction, and is generally fringed, tipt, or occasionally 

 completely covered by parasitical AlgaD, such as Udocarjms silmdosus. 



EXPLANATION OF PLATE CXLVIIL 



Fig. 1. — Laminaria bulhosa, young frond, natural size. 

 2. — Transverse section of same. 

 3. — Spores. Botli magnified. 



