Distribution of the Laminar laceoe. 371 



Hope in the neighborhood of the 25° line, and on the coast of Japan 

 both north and south of the 25° line. fJlopteryx is found with the 

 JEcklonim in Japan. At Terra del Fuego, JEcklonice are very scarce, 

 probably because the isothere of 10° passes through the straits of 

 Magellan. A form of EcMonia radiata (Turn), J. Ag. is found 

 growing at the Canary Islands' which are between the lines of 20° 

 and 25° and nearer to the latter. 



The three species of Lessonia^ L. fuscescens, Bory, L. nigrescens, 

 Bory, and L. ovata, Hook. & Harv. are all inhabitants of strictly 

 cold waters. All three are found on the shores of Fuegia and the 

 Falklands which are entirely below the isothere of 10°, at Kergue- 

 len Land and Heard Island which are situated upon the isothere of 

 5°, and just below it. L. nigrescens^ Bory, is quoted from the coast 

 near Monterey, but there is some doubt as to whether this form is the 

 true L. nigrescens^ Bory, or a new species. L. Lamin<Ariceoides, P.& 

 R., inhabits the coast of Kamtschatka and comes within the, 10° 

 line. L. Suhrii, J. Ag. seems to be a species of warmer waters. 

 It is found at Valparaiso between the 20° and 25° isotheres and at 

 Tahiti where it is much warmer than at Valparaiso, 



The species of Postelsia and Dictyo neuron, as well as Nereocystis 

 Lutkeana, P.&R. occur between 15° and 20°, but N. gigantea, 

 Aresch. occurs between 20° and* 25°, and not north of the 20° line 

 as far as is known. 



Macrocystis pyrifera, Ag. has perhaps the most extended range 

 as regards temperature of any species. It is found floating, down 

 to the region of permanent ice. It grows at Kerguelen Land at 

 5°, is very abundant at Fuegia and Behring Sea, both within the 

 10° isothere, but it also extends up on the western coast of South 

 America and down on the western coast of North America to about 

 20°, and is even found extending somewhat beyond this line in 

 Australia and the Cape of Good Hope. It is reported from Tahiti 

 within the isothere of 25°, but whether attached or floating is not 

 stated. 



When we come to inquire into the reasons for the different pecu- 

 liarities of distribution such as the more marked ones mentioned 

 above, we find that much may be inferred from the particular direc- 

 tions taken by the currents and by considering also the relations to 

 the temperature of the waters inhabited b}'- the different forms. 



^ Cwpea Inruncinata^ Mont in Webb et Berthelot, Hist. Xat. lies Canaries, vol. iii, 

 Pt. 2, p. 14f\ PI. 7, 1840. 



