191-i] Setchell: The Scinaia Assemblage 133 



furcellata, Sc. complanata, and the Florida species, Gloiophloea 

 HaUiae. There is then a representative of both the cylindrical and 

 the complanate groups of true Scinaia and one representative of 

 Gloiophloea. In the NorthM^est North America-Northeast Asia region, 

 viz., the North Pacific (i.e., above the tropic of Cancer), on the other 

 hand, there are eight (out of nineteen) species and all three genera 

 represented. In fact, no group or subgroup lacks representation, even 

 that of the constricted Scinaia species having one representative. 

 This general mixture of representative forms will probably be found 

 characteristic of many other groups of algae as well. It is certainly 

 very characteristic of the Laminariaceae (cf. Setchell, 1893, pp. 355- 

 358). Two other areas stand out and are more or less related, viz., 

 those of the Australian seas or South Pacific (south of the tropic 

 of Capricorn) and the Indian Ocean (including the Cape region of 

 South Africa). The South Pacific region possesses three species 

 representing all three genera, but the species of Scinaia is of the regu- 

 larly constricted type. The Indian Ocean (or South Atlantic?) tem- 

 perate region is known to have two species, one a constricted Scinaia, 

 the other a Gloiophloea. The intermediate tropical regions between 

 these two south temperate (or subtropical) regions and the north 

 temperate and subtropical Pacific regions, viz., the tropical Indian 

 Ocean and tropical Pacific, show only two species, both of the con- 

 stricted type of Scinaia. 



In summary, then, it may be said that Scinaia seems to be essenti- 

 ally a northern hemisphere type, since nine of its eleven species are 

 confined to a position north of the equator and these represent all the 

 various types of structure within the genus, while on the other hand 

 only two species of Scinaia, and those two restricted to the constricted 

 type, are found south of the equator. Of the other genera, Gloiophloea 

 has three species in the southern hemisphere and three in the northern 

 while Pseudoscinaia has one species in each hemisphere. Yet, arguing 

 from the similar distribution of Pacific and Indian Ocean Laminari- 

 aceae, the center of distribution is probably austral and the northward 

 extension along the western coasts of the Americas to Japan a later 

 development. In fact, the Gloiophloea and Pseudoscinaia species, in 

 their distribution, call strongly to mind the distribution of the 

 Lessonioid and Ecklonioid Laminariaceae in their relation to members 

 of the other tribes of kelps. That this is also true of certain other 

 families and genera of marine algae is also apparent and will give 

 an added interest to the study of antarctic and australio-indio-pacific 



