REPORT ON THE PELAGIC FISHES. 3 



and strangers to the pelagic fauna. The Challenger collection contains several instances of 

 such irregular occurrences, viz., Hemerocoetes, Gobius, Fundulus, Mursena. 



Thus, the pelagic fauna comprises a very varied assemblage of forms : not only fishes 

 excelling above all others in the power of swimming with regard to rapidity as well as 

 endurance of motion, but also species in which the power of locomotion is almost 

 reduced to the faculty of floating on the surface, without resistance, at the mercy of 

 wind and current, or of retaining their hold on other floating substances, like sea weed, 

 logs of wood, &c. It comprises fishes which can raise themselves out of the water in 

 short flights, and others which are provided with a special apparatus to attach themselves 

 to a rapid swimmer, thus partaking of all the advantages derived from his power of 

 locomotion. Many accompany ships, large fishes. Medusae, any floating object, partly 

 as commensals, partly for protection. All are carnivorous. They seem to descend during 

 very stormy weather to a depth to which the violence of the surface agitation does not 

 reach. And certainly all nocturnal forms pass the day at some depth, coming to the 

 surface during the night only ; they are provided with luminous organs like many 

 bathybial forms, and, indeed, form a transition to the deep-sea fauna. 



