222 SEAWEEDS 



The Geographical Distribution of the order is 

 throughout all seas. The British genera have already 

 been indicated, and the others, too numerous to 

 particularise here as regards distribution, are some of 

 them local, but most with a fairly wide range. The 

 British forms have mostly a wide distribution else- 

 where in the ocean. 



RHODYMENIACE.E. 



General Characters. More Rhodophycew probably 

 conform to this type than to any other, and it is sub- 

 divided into a number of important families. The 

 carpogonial branches and the parent cells of the 

 auxiliary cells are developed in close proximity and 

 form definite procarpia. After fertilisation has been 

 effected the auxiliary cell is developed, and with it 

 the fertilised carpogonium enters into conjugation 

 by means of a very short ooblastema filament, the 

 auxiliary cell sometimes sending forth a short 

 process to meet it. Usually, and this is true of most 

 Rhodophycecc, the carpogonial branch is so curved 

 that the carpogonium is brought into close vicinity 

 with the auxiliary cell, and the ooblastema filament 

 is therefore either very short or may be suppressed 

 owing to the actual contact of these bodies. The 

 auxiliary cell after this conjugation sends out the 

 gonimoblasts towards the outside of the thallus, and 

 the following families are established mainly on 

 variations in this process, and its results in the form 

 of cystocarpic fruits. 



