304 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY 



In '00: On Tune 9th, 1,97-5; on August 2nd, 498; on 

 November 1st, 115 ; and on December 17th, 164. 



In the larger nets, on occasions, some even greater 

 numbers were obtained, such as 2,300 in the shear-net, on 

 March 31st, '09, 2,050 in the large Nansen net on 

 August 4th, '09, and 3,408 in the Yngel net on 

 August 8th, '08. If we omit these larger nets, the 

 monthly averages for the three years in the open sea are 

 in all cases smaller than the corresponding figures for bay 

 hauls. 



The following table gives the totals for the three 

 years, and shows a remarkable constancy in the total 

 number of Sagitta captured, and in the numbers per haul. 

 When 44 is the average number caught, it is remarkable 

 that the poorest year does not fall below 42, and the 

 richest does not rise above 48 : — 



Year. 



Total 



equivalent 



hauls. 



Total hauls 

 in which 

 Sagitta is 



represented. 



Total No. 

 of Sagitta, 



Average No. 

 Average No. in hauls 

 in all hauls. where 



represented. 



1907 



1908 



1909 



610 

 571 

 754 



370 

 353 

 453 



17,658 

 14,675 

 19,280 



29 

 26 



26 



48 

 42 

 43 



1907-8-9 



1,935 



1,176 



51.613 



27 



44 



In '07 the average number per haul at the maxima is 

 126 in July and 127 in November, and in '09 the greatest 

 average is 209 per haul in June. The numbers are not so 

 great in '08. The minima in '07 and '08 are 2 per haul, 

 in February. Sagitta seems to breed twice in the yer.r 

 (spring and autumn), although some reproducing 

 individuals may apparently be found in any month. The 

 summer maximum is probably the result of the spring 

 brood, and it is noteworthy that this climax in the Sagitta 

 population curve occurs distinctly later than the great 



