420 SCIENTIFIC ADVANTAGES OF AN ANTARCTIC EXPEDITION. 



than the number obtained in eight deep hauls with the trawl and dredge 

 in the Kerguelen region of the Southern Ocean, in depths exceeding 

 1,260 fathoms, in which eight hauls 272 species were obtained. Obser- 

 vations in other regions of the Great Southern Ocean, where there is a 

 low mean annual temperature, also show that the marine fauna around 

 the land in high southern latitudes appears to be very poor in species 

 down to a depth of 25 fathoms, when compared with the number of 

 species present at the mud line about 100 fathoms, or even at depths 

 of about ti miles. 



in 1841 Sir James Eoss stated that the animals he dredged off the 

 Antarctic continent were the same as those he had dredged from similar 

 depths in the Arctic seas, and he suggested that they might have 

 passed from one pole to the other by way of the cold waters of the deep 

 sea.^ Subsequent researches have shown that, as with jjelagic organ- 

 isms, many of the bottom-living species are identical with, or closely 

 allied to, those of the Arctic regions, and are not rej)resented in the 

 intermediate tropical areas. For instance, the most striking character 

 of the shore-fish fauna of the Southern Ocean is the reappearance of 

 tyj)es inhabiting the corresponding latitudes of the Northern Hemi- 

 sphere an d not found in the intervening troi^ical zone. Tliis interruption 

 of continuity in the distribution of shore fishes is exemplified by species 

 as well as genera, and Dr. Giinther enumerates eleven species and 

 twenty-nine genera as illustrating this method of distribution. The 

 following are among the s];)ecies: Ghimsdrsk {Chimwra monstrosa), two 

 species of dogfish [Acanthias vulgaris and A. hlainvilU), the monkfish 

 {BMna squatina), John Dory {Zeus faber), angler {LopMus piscatorius), 

 bellows-fish [Centriscus scolopax)^ 9,j)v?kt {Ghipea sprattus). The genus 

 by which the family Berycidre is represented in the southern temperate 

 zone (TracMchthys) is much more nearly allied to the northern than to 

 the tropical genera. "As in the northern Temperate Zone, so in the 

 southern, * * * the variety of forms is much less than between the 

 Tropics. This is especially ai)parent on comx)aring the number of 

 species constituting a genus. In this zone genera composed of more 

 than ten species are the exception, the majority having only from one 

 to five." u * * * PoZ2/29r^o% is one of those extraordinary instances 

 in which a very specialized form occurs at almost opposite points of the 

 globe, without having left a trace of its previous existence in, or of its 

 passage through, the intermediate space." 



Speaking of the shore fishes of the Antarctic Ocean, Giinther says: 

 "The general character of the fauna of Magelhaeu's Straits and Ker- 

 guelen's Laud is extremely similar to that of Iceland and Greenland. 

 As in the Arctic fauna, Chondropterygians are scarce, and represented 

 by Acanthias nulgaris and species of Raja. * * * As to Acanthop- 

 terygians, Oataphracti and ScorpoBuidte are represented as in the 

 Arctic fauna, two of the genera [Sehastes and Agonus) being identical. 



' Antarctic Voyage, page 207. 



