It will be noted thai the general character of the 

 curves is similar, though the catch in the hay is 

 consistently greater than that at sea. The less sudden 

 diminution in the number of Diatoms in the bay from 

 April 10th to April 17th will be observed, and the sudden 

 drop which then follows, bringing the curves close 

 together b}^ the 23rd of the month. 



The numbers of the total Diatoms from the hauls in 

 the open sea during a month in spring are as follows : — 







Average 



3-day 



Date. 



Hauls. 



per haul. 



average. 



Mar. 29 



4 



45.162 



_ 



April 1 



3 



103.333 



111,998 



2 



2 



187,500 



209.055 



4 



4 ... 



336,333 



198.722 



5 



2 



72,333 



230,111 



8 



... 3 ... 



281,667 



142,133 



9 



5 



72,400 



136,133 



10 



6 



54,333 



56,578 



11 



4 



43,000 



44.175 



13 



6 



35,192 



32.811 



15 



4 



20,240 



23.465 



16 



8 



14,962 



16,651 



18 



4 



14,750 



13,237 



19 



4 



10,000 



8.349 



22 



4 



297 



3.746 



23 



6 



942 



551 



24 



4 



415 



661 



25 



6 



625 



1,780 



26 



4 



4,300 



3.880 



27 



7 



6,714 



— 



* By " three-day averages " is meant taking always the average of 

 the three adjacent days upon which catches were made, i.e., the 

 average of the 1st, 2nd and 3rd, then of the 2nd, 3rd and 4th, then of 

 the 3rd, 4th and 5th ; and so on. 



Bay Diatoms throughout the Yeah. 



A general inspection of the nnsmoothed curve shows 

 a well-marked maximum at the end of March and earlier 

 part of April. The marked increase of Diatoms, and 

 also of Copepod nauplii, towards the end of March is seen 

 well in the surface hauls taken in Port Erin Bay on the 

 following three dates: — 



