90 New York State Museum 



fathoms. The forms here are incrusted with a deposit 

 •of lime which gives them the appearance of corals, hence 

 the name. The Laminariaceae are brown algae and in- 

 clude the seaweeds that go under the names of Oarweed, 

 Tangle, Sea Colander, Devil's Apron etc. In this group 

 are seaweeds of enormous size, the largest known, found 

 in southern waters and off the Pacific coast of North 

 America. One, Macrocystis, has been reported with a stem 

 one-quarter of an inch through, 700 to 1500 feet long, 

 the leaflike part or lamina 50 feet long, and air vesicles 

 as big as eggs. A form occurring on our northwest coast 

 has a 300-foot stalk, a barrel-shaped air vesicle six or 

 seven feet long bearing a tuft of fifty odd forked laminae, 

 30 or 40 feet long. 



Struggle for Existence in Littoral Realm 



The environment of the pelagic and abyssal realms is 

 simple and uniform and life therefore is so easy that 

 there is no fierce competition. In the littoral realm con- 

 ditions are quite different. The struggle for existence is 

 hard, and it is particularly severe, even fierce, in the 

 strand area. The conditions with which the shore ani- 

 mals must contend are a sum total of those brought about 

 by the effects of tides, currents, waves and temperature 

 and salinity of the water. Not only are these factors to 

 be reckoned with but there is in addition a conflict among 

 the animals themselves and even competition within the 

 species. 



Effects of tides. The tides, with their rise and fall 

 twice daily, force upon the life of the strand or tidal 

 area, that is, the lower forms that are not capable of rapid 

 displacement, the necessity of adapting themselves to 



