170 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Explanation of Plate I. 



Cultures of l/50th part of a mussel in neutral-red, bile- 

 salt, lactose agar. (See pp. 136-7.) 



Fig. 1. The original sample of mussels taken from the 

 training wall in the River Lune. 



Fig. 2. The same mussels re-laid for six tides. 



Fig. 3. The same mussels re-laid for four tides. 



Explanation of Plate II. 



Fig. 1. Culture of l/50th part of a mussel from Barmouth, 

 winter of 1915. (See p. 140.) The liquid inoculated was very 

 turbid, so that the medium is greatly discoloured. There were 

 eight red colonies in the plate. 



Fig. 2. A similar culture made from Barmouth mussels 

 from a neighbouring bed, taken in the summer of 1913. The 

 red colonies are very numerous and there is a large patch of 

 small, partially fused colourless colonies. 



Plate III. 

 Lower part of the Estuary of the Lune. 



