PH HOPHYCE A 85 
do these cryptostomata occur in association with the 
sporangia. In its case the cryptostomata are found 
on the sporangium-bearing surface, though repeated 
observations have failed to discover sporangia within 
the cryptostomata. They stop at the brink of the 
cavity, and indeed overhang it. 
The Geographical Distribution of the order 1s 
throughout the temperate and polar seas, being 
limited by the warm waters on the one hand and 
the permanent ice on the other. Laminaria Schinzw 
just enters the tropics at Walfisch Bay on the 
south-west African coast, but within the influence of 
a cold current. Laminaria and its immediate allies 
are characteristic of the northern seas. Lessonia 
inhabits the Pacific north and south, while Macrocystis 
has an immense range in the southern seas, and in 
the Pacific up the whole American coast to Alaska 
and over to the coast of Asia at Kamtschatka. It 
does not extend up either the African or South 
American shores of the Atlantic to any extent. The 
Pacific coast of North America, otherwise rich in 
Laminariacee, possesses the peculiar genera Dictyo- 
newron, Postelsia, Nereocystis, Cymathwre, Pterygo- 
phora, Egregia, and Hisenia, many of them limited 
to California, and all of them with only one species 
except Nereocystts. Alaska has thirty species, and 
California, so rich in generic types, has fifteen, but 
they have only three of them in common. Jeklonia 
occurs in the southern seas and in Japan, while 
the too numerous species of Alaria are all northern. 
The genera occurring in the British seas are Lamin- 
aria, Saccorhiza, Alaria, and Chorda. 
