Ichthyologiske notiser [. 81 
In the northern localities (Lyngen, Varangerfjord) P.12 is some- 
what more frequent than P.10. As KROYER (1845, II) for nine 
specimens from Denmark has P.11 for three and P.10 for six 
individuals and Day (1889) has P.10 for English specimens, 
P.10 appears to be the normal number for the species at its 
southern limit of distribution. If we assume that the Arctic 
specimens represent the primary appearance of the species and 
the occurrence as far south as the British Channel as an invasion 
during Glacial times, the variation of the number of rays in 
D., A. and P. may be explained as the result of the adaptation 
to boreal conditions, the reduction in the number of the fin-rays 
being most advanced at the southern range of distribution where 
the boreal conditions are most marked, diminishing northwards. 
[The zoogeographical work of N. v. HOFSTEN, “Die Fische 
des Eistjordes” (Kgl. Svenska Vetensk. Akad. Handl. 54, No. 10, 
Stockholm 1919.) came into my hands when these notes were 
concluded. In the opinion of this author H. platessoides is a 
true boreal species which has spread to Arctic waters in more 
recent times. His reasoning, dealing mainly with the different 
spawning-time in boreal and Arctic waters, has not altered my 
view. In this connection V. HOFSTEN pays no heed to the 
variation of the species, though he admits that perhaps an 
Arctic and a boreal form may be distinguished. A western and 
an eastern form he does not accept, his specimens from Icefjord, 
Spitsbergen agreeing with 7. hippoglossoides Fabr. from Green- 
land. In 16 specimens the number of rays in the pectoral varied 
im the following way: P.13 in two, P.12 in nine and Pt! in 
five specimens. When, however, V. HOFSTEN takes the boreal 
form as the primary one, he owes us an explanation how then 
this form has the lowest number of rays in D., A. and P. and 
why the eastern Arctic form comes nearest to or is identical with 
the western form, whose distribution southward seems to follow 
the Arctic Labrador-current.] 
Glyptocephalus cynoglossus (L.). Of our Pleuronectids this 
species has the greatest bathymetrical distribution and is the 
most characteristic fish of the soft bottom in the varying depths; 
— in the North Sea occurring already at 35 fths., more abun- 
dant, however, when the depths are 50—100 fths.; in the Nor- 
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