Fishes of 1907 Cruise 227 



area, all but one (Sebastes marinus) occur at similar depths off the 

 west and south-west of Ireland ; while of the six species (excluding 

 the pelagic Scopehis glacialis) taken in the cold area, not one is 

 known to occur off the Irish coast. The only species common to both 

 areas is Sebastes marinus. 



Further, of all the fishes recorded from the cold area, not a single 

 bottom-living species, with the solitary exception above mentioned, 

 has been found south or west of the Wyville-Thomson ridge ; while 

 the numerous species which have been taken immediately to the 

 south or west of the ridge (again excepting Sebastes marinus) are all 

 known from the deep water of the Irish Atlantic slope or from the 

 Lusitanian region. 



Among the genera and species typical of the two regions, we may 

 mention : in the cold area, Lycodes, Lycodonus, Liparis Eheinhardti, 

 and Motel/a Rheinhardti ; and in the warm area, Centrophorus, 

 Macrurus, Alepocephalus Criardi, Haloporphyrus eques, Synapho- 

 branchus pinnatus, and Epigonus telescopium. 



Cases are even to be found of closely allied species each confined 

 to one area. Thus Cottunculus Thomsoni is found in the warm area 

 at a bottom temperature of about 7° to 8° C, and ranges south from 

 its northern boundary to the north-west coast of Africa ; while 

 C. microps occurs in the cold area at a bottom temperature of about 

 0° to -2° C, and ranges northwards to the neighbourhood of Spitz- 

 bergen. Yet both these species have been taken at temperatures of 

 o'h° C. between Iceland and Greenland (Liitken, 1898), and at tem- 

 peratures between 3'9° C. and 7"7° C. by the Albatross in the Western 

 Atlantic. It is, therefore, quite probable that the difference in the 

 faunas of the two regions is in part rather due to the sudden change 

 in temperature than to the absolute difference. Some, however, of 

 the species of the cold area — e.g., Lycodes endipleurostictus and Lyco- 

 donus flagellicauda — are only known to occur at very low tempera- 

 tures ; while other species found in the warm area — for example, 

 Alepocephalus Criardi and Epigonus telescopium — are distinctly 

 warm-water fishes. 



29—2 



