44 37) Sigurd Johnsen. 
It is reasonable to assume that the number of vertebre will be 
still lower in the Mediterranean and that the specimens there — 
will prove to be racially distinct. The species seems to occur — 
principally in the northern parts of the western Mediterranean, 
where spawning takes place in winter. 
Among the coast fishes from deeper water the most striking 
parallelism is that one which is presented by the genus Gadi- 
culus. G. argenteus Guich. is known from the Mediterranean 
and adjacent coasts of the Atlantic, G. thori Schmidt ranges from 
the Irish waters to Norway, being common in the fjords of 
southern Norway. The regions of distribution of the two species 
seem to meet off the west coast of France. The distinction of 
the northern form from the southern one was first demonstrated 
by Johs. Schmidt (1913) and his opinion was based partly on 
differences shown by the larval stages, partly on the number of 
vertebræ, 39—41 in G. argenteus, 41—43 in G. thori. 
The relation between Gadus minutus Miller and G. capelanus 
Risso would seem to be much the same as between the two 
forms of Gadiculus. G. minutus ranges from Norway to the 
north coast of France, while G. capelanus is confined to the 
Mediterranean and has long been held as identical with the 
northern form. According to the account given by Fage (1911) 
G. capelanus appears to be, however, (in a certain character) 
more primitive than G. minutus and both forms should be 
regarded as offshoots from G. luscus. 
The data enumerated above indicate, I think, that among the 
fishes of the Mediterranean are representatives of boreo-Atlantic 
character (from the transitional zone between the Polar zone and 
the circumtropical zone) as well as of more southern forms. 
Ås regards the oceanic forms and the forms occurring near 
the coast on both sides of the Atlantic, the Atlantic stock must 
be supposed to represent the mother-stock from which the Medi- 
terranean stock is an offshoot. More uncertain is the relation 
between the forms confined to the eastern side of the Atlantic 
e. g. the two species of Gadiculus, whether here the northern or 
the southern form is the primary one. In favour of the former 
assumption is the fact that the centre of distribution of the 
Gadids is in northern waters, and, further, that of the two forms 
the northern one, G. thori, has the largest number of vertebræ 
