PKEFACE. 



Had the responsibility of the production of the Narrative of the Cruise rested 

 with the same members of the Expedition from the commencement, a some- 

 what different method would probably have been followed in the preparation 

 of this volume. The arrangement of the matter and the style have been 

 largely determined by the circumstances arising out of the change of Captains 

 during the Cruise, the unexpected death of Sir C. Wyville Thomson in 1882, 

 and the necessity for publication before the completion of many of the 

 special Reports. 



It is hoped, however, that the volume will be found to contain a faithful 

 record of the Work of the Expedition, and as complete an account of the 

 scientific results as is possible in the present state of the investigations. 



A considerable part of Professor Moseley's contribution to the Narrative 

 is in the form of revised and modified extracts from his Journal, published 

 in 1877. 1 



With respect to the depths assigned to the Zoological specimens, it may be 

 well to state that the Naturalists of the Expedition have simply recorded 

 the greatest depth to which the dredge or trawl was believed to have 

 descended at each Station. It will be evident that the instrument may 

 have been occasionally dragged into slightly deeper or shallower water than 

 was recorded by the sounding line, and what is of greater consequence, the 

 trawl or dredge may have caught animals while sinking through the water 

 or being hauled up again. In the great majority of cases there is little 



1 Notes by a Naturalist on the Challenger, London, 1877. 



