78 TBANSACTIONS LlVEBPOOL BIOLOGICAL SOCIETY. 



from the ocean up St. George's Channel and along the 

 west side of the Isle of Man (see map). This proved to 

 be an important spawning ground for Plaice, Dabs, 

 Flounders, Cod, Haddock and Whiting, as not only were 

 fish distended with ripe ova brought up in the trawl but 

 large numbers of transparent pelagic fish ova and embryos 

 in various stages of development were obtained in the 

 surface tow-nets. 



This was the first piece of actual evidence obtained as 

 to the spawning place of the food fishes of this district. 

 Subsequent trawlings and tow-nettings during the sum- 

 mer showed that this is probably the great spawning 

 ground for this part of the Irish sea, and it is noteworthy 

 that it is not a bank, but is actually a depression on the 

 average 8 fathoms deeper than the neighbouring sea. This 

 locality has a remarkably rich fauna. The small bivalve 

 mollusc Scrobicularia alba, which is a favourite food of 

 various edible fishes, is very abundant, along with many 

 rarer things, such as the beautiful Nudibranchs Tritonia 

 hombergi, Eolis tricolor, and Dendronotus arborescens, 

 the crab Gonoplax angulatus and the Pennatulid Vir- 

 gularia mirabilis which is constantly browsed on by 

 fishes of the Cod tribe. The bottom here is a soft bluish 

 black mud with which we find great numbers of the long 

 spiral mollusc Turritella terebra, and the egg masses of 

 this and other molluscs when brought up from the bottom 

 on long lines or in nets have frequently been mistaken by 

 fishermen for the spawn of food fishes. It is well-known 

 now that our ordinary food fishes, except the Herring, 

 produce pelagic eggs which are not deposited at the 

 bottom, but which rise to near the surface of the sea 

 where they undergo their development while floating freely. 

 Although it is obvious that there must be determining 

 factors which attract fish from great distances to certain 



