1&2 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



conditions on the beds, and it becomes necessary to fall 

 back upon other methods which may not give altogether 

 conclusive results from a critically scientific point of view. 

 To remove animals from their natural surroundings and 

 place them in confinement in a limited area of water is 

 undoubtedly detrimental to life processes at first. After- 

 some time the effects produced by the change may how- 

 ever be diminished, and the animals become acclimatised 

 and live probably very much as they would have done had 

 they been left in their original state. We are thus 

 enabled to carry on observations which would be quite 

 impossible under natural conditions. 



Large samples, about \ cwt., of mussels were collected 

 from the Roosebeck outer scar and from a scar in Barrow 

 Channel Avhich only ebbs dry at low water of spring tides. 

 These were placed in the tanks in September, 1899, and 

 kept under observation for twelve months. A constant 

 current of sea water was maintained, and from time to 

 time, usually twice a week, small quantities of mud, known 

 to contain diatoms, &c, were added to supply the animals 

 with food. The animals were examined microscopically 

 at intervals, and the reproductive organs compared with 

 samples taken direct from the beds. The rate of develop- 

 ment was found to be practically the same in the mussels 

 in the tanks and in those on the beds. 



On May 6th the mussels from both beds commenced to 

 discharge eggs. These were isolated and examined under 

 the microscope. No development took place. No ripe 

 males were found at this period, and it may be concluded 

 that these eggs were not fertilised. The mussels con- 

 tinued to discharge eggs which underwent no change until 

 June 14th. On Tune 13th the first obvious discharge of 

 spermatozoa occurred. This was from the mussels from 

 Barrow Channel, and so abundant was the supply that 



