OCEANIC ICHTHYOLOGY 



INTRODUCTION. 



OiTR purpose has been to present in Oceanic Ichthyology a discussion of all forms 

 of fishes found in the seas of the world, both pelagic species and those occurriiin' at depths 

 greater than 500 feet, especial prominence being given to those species which are found in 

 the Atlantic Ocean, most of which we have had opportunity to study. All oceanic fishes 

 are included, partly because it is not yet possible to distinguish strictly between the two 

 classes, and partly because the pelagic forms have, in part at least, been mentioned in the 

 discussions by all previous writers on "deep-sea fishes." 



By Oceanic fiahes we mean those deej) sea and i)elagic species which dwell in the open 

 ocean far from the shore, either at the surface, at the bottom, beyond a depth of 500 feet, or, 

 if such fishes there be, the intermediate zones. 



Oceanic Ichfhyoloyy is that branch of ichthyology which is concerned with their study. 



Deep-sea fishes are those which are found at a depth of 1,000 feet or more, without 

 reference to the question whether or not they also occur in shallower water. The limit of 

 500 feet is taken for convenience in the study of the origin of local deep-sea faunas. The 

 limit of 100 fathoms is that ordinarily in use. The Reports of the GhaUeMjcr class as 

 "deeii-sea deposits" all those below 100 fathoms depth. The zont? between the litteral 

 zone, and the bathybial zones, 500-1000 feet, is called the "liemibathybial zone" 



Pelagic fishes are those which live far from land and at a distance from the bottom, 

 rarely a])proaching the shore excei)t when driven by wind or current. It is these which 

 are most closely associated with the "Plankton," and were included in it before the mean- 

 ing of the term, as proposed by Henseu, was limited by Ha'ckel. S(nue of these, which 

 occur at considerable depths, we call "bathypelagic." 



We cannot claim that in the present memoir we have brought forward any conclusions 

 which are new to science, though a great number of new facts are recorded. ^Ve hope, 

 however, that we have succeeded in the attempt to bring the information which we have 

 ourselves been able to obtain into proper relationship with the mass of similar knowledge! 

 already recorded, and that our descriptions are so accurate and full that the deterioration 

 or loss of the material studied, much of which was in very fragmentary and pre('arious ('ou- 

 dition when it came to us, may not be entirely disastrous. We have tried to assemble all 

 existing data about oceanic fishes and to arrange them in such a manner that tiicy may be 

 serviceable to naturalists in other. fields for comparison and studj', as well as to ichthyolo- 

 gists for ready reference, when at a distance from the rather extensive group of books which 

 must now be consulted even for the casual identification of a deei)-sea fish. We have also 

 endeavored to sum up the conclusions reached by previous students before incorporating 

 our own results with those of our predecessors.* 



NoTK. — I Ikivc ill pri'jiuratioii iiiul sIimII scxm piililish ;m I'xteiidiHl study of tlic f;eoi;ra|ilii<al ilLstiilMitiim 

 of deep-se;i aud pelagic lislies, aud of tho origin of tho several bathybial lisli faunas. 



G. liRowy GooDK. 



