INTRODUCTORY. 



elaborately and delicately formed, and more ex- 

 quisitely beautiful in their soft shades of colouring, 

 and in the rainbow tints of their wonderful phosphor- 

 escence, than the fauna of the well-known belt of 

 shallow water teeming with innumerable inverte- 

 brate forms which fringes the land. And the forms 

 of these hitherto unknown living beings, and their 

 mode of life, and their relations to other organisms, 

 whether living or extinct, and the phenomena and 

 laws of their geographical distribution must be 

 worked out." 1 



The most important investigations of the sea 

 depths were those by John Ross, in Baffin's Bay, in 

 1818 ; by James Ross, in the Pacific Ocean, in 1843 ; 

 by Lieut. Joseph Dayman, in the North Atlantic, in 

 1857; by Dr. Wallich, in the North Atlantic, in 

 1860 ; by Chydenius and Torell, near Spitzbergen, in 

 1 86 1 ; by Carpenter, Jeffreys, and Thomson, in the 

 North-East Atlantic, in 1868 and 1869; by Pour- 

 tales, in the Gulf Stream off Florida, in 1869; and 

 the famous "Challenger" Expedition, from 1873 to 

 1876. Between the first and last of these, extending 

 over three-quarters of a century, the steps were 

 gradual, but all tending to a distrust of the notion 

 that there was a zero of animal life at a limited 



1 " The Depths of the Sea." By C. Wyville Thomson. 

 London : Macmillan & Co. (1873), P- 4- 



