SEA-FISHERIES LABORATORY. '205 



the total amount obtained is much the same, but is made 

 up of rather different constituents, Biddul'phia mobiliensis, 

 Chaetoceros contortum, and some other forms, being more 

 abundant on the 9th ; while C. debile, present on 

 the 9th, is altogether absent on the 10th. The very 

 large number of Echinoderm Plutei on April 9th is 

 noteworthy ; their occurrence is very sporadic ; they 

 were present again in large numbers on April 19th, when 

 1,000 were taken in the haul corresponding to I. A. on 

 April 9th. But, on the whole, the resemblance between the 

 two hauls is more striking than the differences, the list 

 of organisms is very nearly identical in the two sheets, 

 and the general run of the numbers is for the most part 

 the same. 



Another interesting comparison, in this case of two 

 separate but not distant localities taken practically at the 

 same time, is seen in the Forms (20 and 21) that are given 

 here for April 10th. No. 20 is from off-shore station I, 

 five miles X.W. of Bradda Head, while No. 21 is from 

 the second station ten miles off land along the same line. 

 Both are in the open sea and at both the same set of nets 

 (Hensen, Nansen, Weighted, and two Surface nets) were 

 used, within an hour; but in the first locality the total 

 bulk of the plankton caught was 104 c.c. while in the 

 second locality it was only 39 c.c. ; and it will be noticed 

 in running the eye down the figures for the different 

 organisms that the five-mile station yielded far more in 

 the case of Diatoms and Dinoflagellates and fish-eggs, but 

 less in the case of Copepoda. The total Diatoms amount 

 to over 3| millions at five miles as against 324,000 at ten 

 miles ; the total Dinoflagellates is 55,000 at five miles and 

 13,000 at ten miles ; while the Copepods are under 3,000 

 at five miles and nearly 5,000 at ten miles. The general 

 run of organisms present is the same in the two cases, 

 although the total numbers differ so much. 



