THEIR RELATIONS WITH THE PAST 229 



Caudan, by the Prince of Monaco's yachts Princesse 

 Alice and Hirondelle, by expeditions from Norway 

 and Denmark, and by the Investigator herself 



But, as Dr Glinther has pointed out, although 

 these fishes exhibit numerous characteristic modifica- 

 tions for life under peculiar conditions, yet they all 

 belong to groups with which we are perfectly familiar. 

 Now this is hardly what we should have expected on 

 the theory that the great ocean basins have remained 

 unchanged, or little changed, from the earliest geo- 

 logical ages. If this theory be true, we should rather 

 expect to find that the fishes of the depths belonged to 

 ancient groups, which ages ago had become modified, 

 beyond any fear of displacement by more modern in- 

 vaders, for the special conditions of abyssal life, but 

 which, in other situations, where the conditions of life 

 had been subject to constant change, had long ago 

 become extinct. We should, in fact, look to the 

 depths — as, indeed, some of the older zoologists 

 actually did look — for a series of living fossils that 

 would fill many gaps between existing orders of 

 fishes. 



But if we do not find that the abysses are peopled 

 by strange relics of the Age of Ganoids, it is certainly 

 true that among the fishes of the deep sea we find, on 

 the one hand, a suggestive number of survivors of 

 groups — such as the Berycoids, and Trichiuroids, and 

 marine Physostomes — which appear to have passed 



