48 MUSSEL CULTURE 



sexes are perfectly distinct, as we have already 

 seen, and impregnation takes place as the eggs, 

 expelled from the parent, float freely in the water. 

 In Scotland, owing to the tricks of a fickle 

 climate, the season at which this spatting takes 

 place is subject to considerable variation. The 

 genital glands show signs of activity and enlarge- 

 ment during the winter months, and all mussels 

 which are likely to spawn may probably be con- 

 sidered as ripe at the end of April. By this it 

 must not be understood that mussels do not 

 spawn before April ; the statement refers purely to 

 the common condition. Many beds may, during 

 warm spring weather, have thrown off great 

 quantities of spat before then. Professor M'Intosh 

 tells us, for instance,^ that in January the repro- 

 ductive organs are well developed, ' and by the 

 beginning of February ripe eggs and sperms are 

 common ' within the mussel. Ripening depends 

 largely on a steady continuance of genial weather, 

 and if this is not vouchsafed, the spatting season 

 is much interfered with. Hence it happens that 

 spatting occurs at very different times in different 

 localities. 



^ Report 071 the Mussel and Cockle Beds in the Estuaries of the 

 Tees, the Esk, and the Humber. Hull, 1891, p. 27. 



