THE BROWN SEAWEEDS OF THE SALT MARSH. 333 
vol. i. р. 127) in 1792 in the Wells Marshes, Norfolk. Very occasionally 
at Blakeney, plants are found showing irregular swellings. Similarly, 
swellings (see fig. 7) occur on the Blackwater forms, sometimes associated 
with characteristic vesicles. However, the absence of vesicles is not 
decisive. А large number of receptacles have been examined and, of these, 
all except two have been strictly dioecious, the sexes being of about equal 
Hig. 4.— Fucus vesiculosus megecad limicola ecad volubilis. Nat. size. 
Intermediate form with vesicles. Blackwater Marshes, Essex. 
frequency. These two exceptional receptacles were borne on plants other- 
wise apparently normal. One of them showed a few hermaphrodite 
conceptacles in the upper part of a male receptacle ; the other bore female 
conceptacles above and male below. Their occurrence does not vitiate the 
main contention that the Blakeney plants are also dicecious and therefore 
referable to Fucus vesiculosus. They are probably reversions to a very 
ancient and primitive hermaphrodite habit in this alga, comparable to the 
reversions occasionally found in the rock species. 
