Remarks on Myctophum glaciale (Reinh.). 35 
The distribution of the M. glaciale in the Mediterranean is 
very peculiar and gives in my opinion a further support to the 
assumption that the occurrence of the species here is of relict 
nature. The main area of distribution is the western basin of 
the Mediterranean, especially the portion of this between Spain 
and the African coast. The Sea of Marmora represents a second 
centre of distribution; the “Thor” found here a rich stock of 
adult and larval stages. The species is, however, absent from 
the Ægean Sea and from the main portion of the eastern basin of 
the Mediterranean, being found here only in the northern waters 
between Italy and Greece and only sparsely. For details I may 
refer to the work of Taning (1918) who has also given a chart 
of distribution where the captures of the “Thor” are represented 
in an instructive way. Taning suggests that the specimens 
found in the eastern Mediterranean may have originated from the 
western principal area of distribution, their occurrence being due 
to the peculiar current conditions of this sea. Of the isolated tribe 
of the Marmoran Sea Taning (1918 p. 38) express his opinion 
as follows:—“The connection between this and the Mediterranean 
race, which must be regarded as the mother stock, seems difficult 
to explain, as the species was not met with at all in the Ægean. 
As the two other species, also occurring in the Marmora (M. be- 
noiti and L. crocodilus), are found in the Ægean, we must 
presume that M. glaciale has passed through the latter sea into 
the Marmora, finding there, in the water layers derived from the 
Mediterranean, suitable conditions for propagation”. 
From this it seems that Tåning seeks the explanation of the 
distribution of the species in the present hydrographical conditions 
of the Mediteranean. I do not think that the currents of the Mediter- 
ranean can account for the distribution of M. glaciale. According to 
to Nielsen (1912, text p. 184—186, pl. XI) the extraordinarily 
salt Mediterranean water runs as an undertow from the eastern 
basin into the western one and further through the Strait of 
Gibraltar into the Atlantic, influencing the waters along the 
coast of Europe as far as south-west of Ireland, as indicated by 
a maximum in the salinity at a depth of about 1000 metres. As 
compensation for this loss of water, there is an inflow from the 
Atlantic through the Straits of Gibraltar. This is a surface-current 
running along the coast of Africa, in the western basin with some 
