352 THE ZOOLOGIST. 
These are all figured by Mr. Collett in the present work, together 
with several other species more or less rare. So far as can be 
judged without actual comparison with the specimens, the plates 
strike us as being most carefully and accurately executed. With 
the exception of Rhodichthys, they are uncoloured, but as full 
details of the coloration are included in the description of each 
species, there can be no difficulty in identification. 
In most of the specimens collected, Mr. Collett, assisted by 
Prof. Sars, was careful to examine the contents of the stomach, 
an examination which, he tells us, proved of considerable interest, 
not only by contributing to our knowledge of the distribution of 
divers invertebrate species in northern latitudes, but also from its 
having substantiated the very remarkable fact that several of 
these pelagic forms of animal life, whose habitat was generally 
believed to be near the surface, possess the power of descending 
to the greatest depth in which deep-sea fishes have been met with, 
where they attain even a larger size than those taken in the 
upper strata of the water. 
The labours of ichthyologists within the last few years have 
brought to light a number of new forms belonging to the genus 
Lycodes, which is now found to comprise a greater number of 
species than any of the other Arctic deep-sea fishes yet known. 
To work out the new species of this genus collected by the 
North Atlantic Expedition, and to determine their precise 
relationship to types already established, must have been no easy 
task; and some idea of the labour bestowed by Mr. Collett on 
this report may be gained by reference—for instance—to his 
remarks upon this genus (pp. 77—84), wherein, after pointing out 
some of the difficulties to be contended with, he gives a critical 
review of the bibliography of the genus, and a tentative summary 
of the species, of which he recognises eighteen. In this single 
chapter we have good evidence of the careful way in which 
Mr. Collett has drawn up his Report, which in every respect is an 
important contribution to ichthyological science. 
We have only to add that, being wisely printed in Norwegian 
and English, in parallel columns, it cannot be regarded as a 
sealed book to English readers, like many valuable scientific 
memoirs of Scandinavian origin which have preceded it. 
