144 COASTAL FISH 



Antipodocottus galathese. It is the only bullhead known to inhabit the 

 southern hemisphere, where it is separated from its nearest relatives in 

 Japan and California by literally oceans of water. Dr. Bolin has tried to 

 imagine how this fish reached the Tasman Sea, in an exciting piece of 

 detective work which can be only briefly summarized. The common ance- 

 stors of the present Californian, Japanese, and Tasman species must have 

 lived off the Pacific coast of North America, some in shallow water and 

 others at a couple of hundred metres. One of the deep-water species, 

 which inhabited an area with a rather narrow temperature range of 

 between 6° and 9° C, migrated during a very warm period westward 

 along the northern fringe of the Pacific, and then in the next cold period 

 was forced southward on the Asiatic side. This became the progenitor of 

 the Japanese genus Stlengis, which has since evolved three species, while 

 those which remained in American waters became the ancestors of the 

 present seven Icelinus species. Alternating glacial and inter-glacial periods 

 forced some of the Japanese bullheads, in their search for lower tempe- 

 ratures, down to deeper waters, and — owing to special oceanographical 

 conditions — not to the north but still further south, along a route which 

 probably followed the Ryukyu Islands, Formosa, the Philippines, New 

 Guinea, the Solomon Islands, and the New Hebrides, to end up near 

 Tasmania, where it now lives at a depth of 600 metres. 



"Such a migration", writes Dr. Bolin, "must have been an arduous 

 one, and it would have been possible only for a form living in compara- 

 tively deep water, water much deeper than is usually inhabited by fishes 

 of this family. It is, therefore, not surprising that the migration has ap- 

 parently been performed only once, and that Antipodocottus is the sole 

 representative of its family in the southern hemisphere." 



Of other Cataphracti, brief mention must be made of the C ottunculidcE , 

 small, degenerate bullheads, of which, in a trawl at 1,000 metres off 

 Angola, we took a specimen of the genus Cottunculoides, about 10 centi- 

 metres long. The three known species had been caught off the Cape, and 

 the one which we obtained, besides being a quite new species, considerably 

 extends the distribution of this genus. 



Whereas the flatheads (Platycephalidce) , which were so common over 



The bullhead Cottunco- 

 loides /rom West Africa, 

 1,000 metres deep. 



