6 DEEP SEA FISHES. 



Previous to the year 1891 almost no deep sea collecting had been 

 attempted in the equatorial regions. On other cruises the "Albatross" 

 had searched the depths off the western coasts of North America from the 

 Gulf of California to Bering Sea. The same vessel and other vessels of 

 the Coast Survey and of the Fish Commission of the United States had 

 obtained a fair knowledge of conditions in the northwestern Atlantic 

 from the Caribbean Sea northward, to which the British steamer " Clial- 

 lenger" also contributed something; the "Challenger" the " Travail- 

 leur," the " Talisman," and other vessels of various European governments 

 rendered a like service in the northeastern Atlantic from tlie Cape Verdes 

 and the Mediterranean northward; the "Challenger" researches added 

 much to ichthyological knowledge of the northwestern Pacific and the Aus- 

 tralian regions, also a little concerning the southwestern Atlantic and the 

 Antarctic ; and the British Indian steamer " Investigator " has done a great 

 deal of work in the northern reaches of the Indian Ocean. The most of 

 these researches were effected far to the north of the equator and a compar- 

 atively small amount was accomplished in southern latitudes. The present 

 collection of the " Albatross " supplies data from the waters under the 

 equator and in a measure provides the means of coimecting the results 

 obtained in the north with those from the south, Avhich latter, however, 

 pertain almost entirely to the shoal water fauna of that region. 



Genera of animals known toward the Arctic regions having been found 

 to occur in the Antarctic, to some extent the fact that they had not 

 been carefully sought in the equatorial waters was overlooked, and a theory 

 of a bipolar distribution with absence from the torrid zone was accorded 

 a considerable amount of favor. Acceptance of this theory was not at 

 all general, for as early as 1880 Giinther had published his belief that 

 separate horizontal regions could not be distinguished in connection with 

 the fishes of the abyssal fauna, yet it was not until 1891, in the present 

 collection, that abundance of material proof that the belief was well founded 

 was secured, — proof that the bipolar theory could not apply to the bathy- 

 bial fishes. So many of the least expected families appear in the collection 

 that there are doubts of the absence from the localities from whicli it 

 was gathered of any of the fishes of the deep sea. The presence of 

 Raiae, Pediculates, Discoboles, Gadoids and Myxinida?, among others, leads 

 one to anticipate the occurrence in the same areas of any of the known 

 fishes of great depths. If the collection is compared with collections made 



