THE COLDER TEMPERATE ZONE. 83 



especially on account of their size, namely, D } Urvilfaa utilis, 

 the Lessonia, and the Macrocystis. 



With two exceptions, the D* Urvill&a utilis exceeds all 

 other seaweeds in bulk. In Kerguelen's Land "its enor- 

 mous and weighty fronds, sometimes ten feet long, and almost 

 too heavy for a man to lift, form the only shelter for the 

 shells and soft animals which there find a refuge from the 

 flocks of aquatic birds that cover the shores, and follow the 

 receding tide." 



The habitat of this seaweed is Tierra del Fuego, the 

 Falkland Islands, and Kerguelen's Land ; it is very abun- 

 dant at half-tide mark and below it ; but it is also found in 

 the open ocean, ranging as far to the north as t( the latitude 

 of Valparaiso, or 33 south, on the west coast of South 

 America, and 50 south on the opposite shores of the same 

 continent," which "will probably be its northern limit." 

 It was observed floating in the open ocean in the meridian 

 of the Cape of Good Hope in the 51st degree, but "does 

 not appear to inhabit or be cast upon the southern extre- 

 mity of Africa." In the Indian Ocean its range is not 

 thought likely to extend further to the north than Prince 

 Edward's Islands, the Crozet group, and Kerguelen's Land. 



" On the other hand, the south latitude it attains is pro- 



