GENERAL BIOLOGY 745 



macrorhinus indictis, 1.8 cm. long. So few of these were 

 captured that I cannot attempt to define their vertical dis- 

 tribution. 



These instances suffice to show that in the ocean the 

 vertical distribution of young stages varies greatly in different 

 species. Certain forms pass the whole of their life-cycle in 

 deep water beyond 500 metres ; others live in deep water only 

 in the adult stage, or at least spend their early life in the upper 

 water-layers ; others, again, pass the whole of their life in certain 

 clearly defined intermediate layers ; while others live in the 

 surface waters all their lives. All these groups are holopelagic 

 forms, but we meet with a group of genuine deep-sea fishes, 



Fig. 537. 

 YoMr\g oi Macrurus. Nat. size, 4.6 cm. Station loi. 



which in the adult stage live along the ocean-floor, while the 

 eggs and fry occur in the water above, at depths varying in 

 different species. These forms remind us of the fishes ot the 

 coast banks, from which they have probably been derived. Of 

 special interest is the fact that we found the pelagic young of 

 Macruridae (see Fig. 537) south of the Azores and at Station 

 loi, between Rockall and the west coast of Scotland, though 

 we have been unable to determine the species. 



The majority of the young fish collected by us belong 

 to the biological group of transparent surface forms, but some 

 of the minute stages may have escaped our notice or may 

 have been damaged beyond recognition by the coarse cloth 

 employed in some of our gear. The various forms contained 

 in our collections have yet to be systematically examined, so 



