192 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



DISCUSSION OF THE OBSERVATIONS. 



The majority of the hauls discussed below were taken 

 from the S.Y. " Ladybird " during the two critical periods 

 of the year, spring (April) and Late summer (August and 

 September), when certain constituents in the plankton 

 attain their maxima of development ; while the other 

 observations were taken throughout the year from smaller 

 boats in the inshore waters of Port Erin Bay. 



During the spring, a month (March 28th to April 

 27th) was devoted to this work from the ik Ladybird," and 

 in the 23 working days during that period we took in all 

 276 samples, an average of 12 per day. 



In the summer and autumn (August 9tlrto September 

 20th) the " Ladybird " was again engaged on this work, 

 and during this period 300 gatherings were taken in the 

 30 working days, an average of 10 per day. On one 

 expedition (September 20th) 36 gatherings were taken in 

 an afternoon, in a small area of only about two miles 

 extent, as follows : — 



Locality A : — 6 miles out, W.N.W. of Bradda, over 30 fms. 



1. Hensen and Nansen nets let down to 30 fms. and hauled up 10 fms. (30-20). 



2. „ „ „ 20 fms. „ „ 10 fms. (20-10). 



3. „ „ „ 10 fms. „ „ 10 fms. (10-0). 



4. „ „ „ 30 fms. „ „ {open to \ (30 . 0) 



(surface j 

 Weighted open net (A) and two surface nets (Al and A2) along with shear net 



(Sh. 1) at 15-20 fms. 

 Weighted open net (B) and two surface nets (Bl and B2) along with shear net 



(Sh. 2) at 7-8 fms. 

 (These each J-hour hauls ; the one set taken immediately after the other). 

 Mill water bottle at 20 fms., strained at the time. 

 ,, ,, 20 fms., strained on shore. 



Locality B : — 8 miles out W.N.W. of Bradda, over 30 fms. 



1. Hensen and Nansen nets let down to 30 fms. and hauled up 10 fms. (30-20). 



2. „ „ „ 20 fms. „ „ 10 fms. (20-10). 



3. „ „ „ 10 fms. „ „ 10 fms. (10-0). 



4. Nansen (alone) „ „ 30 fms. „ ., to surface (30-0). 

 Weighted open net (C) and 2 surface nets (CI and 02) along with shear n< t 



(Bl) at 7-8 fms. 

 Weighted open net (D) and 2 surface nets (Dl and D2) along with shear net 



(B2) at 15-20 fms. 

 (These each J-hour hauls ; the one set taken immediately after the other). 

 Mill water bottle at 20 fms., at 10 fms., and at 5 fms, 



