MARINE BIOLOGICAL STATION AT PORT ERIN 67 



and may have been even more restricted. Under these circum- 

 stances, an observation made solely in the water traversed 

 during the first seven minutes would have given a very different 

 result from that actually obtained ; or, to put it another way, 

 had two expeditions taken samples that evening at what 

 might well be considered as the same station, but a few hundred 

 yards apart, they might have arrived at very different con- 

 clusions as to the constitution of the plankton in that part of 

 the ocean." 



" The Nauplius and Cypris stages of Balanus form an 

 interesting study. The adult Barnacles are present in enormous 

 abundance on the rocks of Bradda Head, and they reproduce 

 in winter, at the beginning of the year. The newly-emitted 

 young are sometimes so abundant as to make the water in the 

 shore pools appear muddy. The Nauplii first appeared in 1907 

 in the bay gatherings on February 22nd (in 1908 on February 

 13th), and increased with ups and downs to their maximum on 

 April 15th. and then decreased until their disappearance on 

 April 26th. None were taken at any other time of the year. 

 The ' Cypris ' stage follows on after the Nauplius. It was first 

 taken in the bay on April 6th, rose to its maximum on the same 

 day with the Nauplii, and was last caught on May 24th. 

 Throughout, the ' Cypris ' curve keeps below that of the 

 Nauplius, the maxima being 1,740 and 10,500 respectively. 

 Probably the difference between the two curves represents 

 the death-rate of Balanus during the Nauplius stage." 



Our reports for the last twelve years fall naturally into 

 two categories — the pre-war series which, from 1907, are largely 

 occupied by the plankton investigations, increasing in intensity 

 and in the variety of experimental nets made use of year by 

 year, and, secondly, the four reports from 1915 onwards which, 

 on account of the restrictions necessarily put upon our work 

 at sea, were devoted in part to laying before our fellow workers 

 and students short oceanographic studies upon the three 



