138 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



circumstances, it is almost impossible to get a complete 

 series of collections for a whole year. A continuous daily, 

 or even weekly, sample from one particular region is apt 

 to be interrupted through conditions of weather and other 

 unforeseen agencies, over which there is no control. 

 Again, a gathering taken once a day, once a week, or once 

 a month, may yield some interesting organisms, but one 

 would like to know what had happened in the interval, 

 whether the organism was only a solitary example or part 

 of a rich, widely-diffused shoal. The only area that is 

 represented at least once every month, in 1906, is Cardigan 

 Bay. This division was dealt with in the last Report, and 

 further consideration of its monthly plankton is, therefore, 

 deferred in the meantime. If the tables giving the 

 occurrence of organisms in the areas investigated be 

 compared, it will be noticed that during July, August and 

 September Port Erin had a greater number of organisms 

 than the other stations during that period. This is 

 entirely due to the way the area was investigated and the 

 large number of samples collected. Professor Herdman 

 chartered the small steam yacht " Madge," and spent his 

 summer vacation making plankton hauls in the open sea, 

 in the vicinity of Port Erin. The region investigated lay 

 mainly between Bradda Head and the Calf Island. The 

 amount of work that was done can be readily understood 

 when it is stated that on the twenty-nine working days 

 when the ik Madge " was at work seventy-three tow- 

 nettings in all were taken. Even after the observations 

 made from the yacht ended, other tow-nettings were taken 

 both inside and outside Port Erin Bay by Professor Herdman 

 and Mr. Chadwick. The result is that during the period, 

 July 22nd to September 30th, seventy-nine collections 

 were made. More than half that number were taken in 

 the latter month. With such a large amount of material 



