166 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



May 25— 



Guinardia flaccida, 60,000, 62,000, 63,000, 54,000 ; 



Rhizosolenia semispina, 1,620,000, 1,120,000, 1,600,000, 1,460,000 ; 



Strevtothcca thamensis, 300, 100, 400, 200. 



Many other similar examples might be given. On the other 

 hand in the case of other species or on other occasions there 

 was more variation, and such cases as 60 and 800 in adjacent 

 hauls can be found. 



It is much the same with the four common species of 

 Dinoflagellates recorded. There again we find cases of con- 

 siderable constancy in the hauls of a series, such as : — 

 May 25—Peridinitim divergens, 46,000, 62,000, 50,000, 44,000 : 

 and other cases of more variation — even in the same series, 

 such as : — 



May 25— Ceratium furca, 6,000, 2,000, 8,000, 1,000. 

 Are we entitled from this to conclude that the Peridinium is 

 very evenly distributed through the water and the Ceratium 

 much less so ? I doubt it. 



The Copepoda, occurring in much smaller numbers, seem 

 also to indicate in many cases a fairly even distribution. 

 Sometimes they occur only in units, and yet each haul of the 

 series shows a few : — 



April 3 — Oithona similis, 8, 4, 3, 3, 5, 11 ; 



3—Pseudocalanus elongatus, 10, 85, 130, 110-, 79, 80 ; 

 ,, 13 — Temora longicornis, 10, 5, 10, 10, 10 ; 

 „ U—Oilhona similis, 20, 20, 20, 20, 20. 



Other cases again seem to indicate considerable variation 

 in adjacent hauls. Which of these contradictory impressions 

 received from an inspection of the results of the hauls is true 

 to Nature 1 If the Oithonas on April 13th had been quite 

 irregularly scattered through the water, is it likely that we could 

 catch exactly 20 in each of five successive hauls ? On the 

 other hand, if they were evenly distributed, how can we account 

 for one haul (April 6th) catching 40 and the next 140, or for 

 the series on May 25th — 20, 80, 460, 290 in the four successive 

 hauls ? 



