264 University of California Puhlicntions in Zoology [Vol. 18 



From these data it is difficult to understand how any seasonal 

 effect could have been responsible for the temperature relations 

 revealed by tables 4 to 6. In the first place section A shows that, while 

 six more hauls were made during June, 1908, in the colder than in 

 the warmer water, the five made in the Avarmer water were, as indi- 

 cated by the mean date, made somewhat later in the month than were 

 the other eleven. According to the hypothesis under consideration 

 this might lead to an excess of solitary forms and a deficiency of 

 aggregate forms in the warmer water. But the differentials revealed 

 by table 4 could not have been due to the influence of this month 

 because the same differentials are shown by table 5, and section B of 

 the above table shows that none of the hauls involved in table 5 were 

 made during June, 1908. Likewise, it is shown by section D that 

 none of the hauls involved in table 6B were made during July, 1908 ; 

 yet the same differentials are revealed by it as by table 4, which 

 obviously means that the differentials could not have been due to the 

 way in which the hauls were distributed throughout July, 1908. 

 Similarly with respect to July, 1909 : section E of the above table 

 shows that no hauls were made in the warmer water between 6 a.m. 

 and 10 A.M. (table 6C), while section F shows that none were made in 

 the colder water between 6 p.m. and 10 p.m. (table 6D). Yet the 

 differentials revealed by tables 6C and 6D, to which these data relate, 

 are identical. 



It is clear, then, that the hypothesis under consideration must 

 justify itself, if at all, on the way in which hauls were distributed 

 during June, 1909. But all five sections of table 8 show : (1) an almost 

 exact equality between number of hauls made in the colder water 

 and in the warmer water ; ( 2 ) an almost identical mean date relative 

 to hauls made in warm and cold water; and (3) that the slight differ- 

 ences in mean date that do exist are erratic with respect to the tem- 

 perature of the water; two instances (section A, and F) indicating 

 that the hauls made in the colder water were also made somewhat 

 later in the month than were those made in the warmer water, while 

 two instances (sections C and E) indicate that the reverse was 

 true. 



To demonstrate completely the inadequacy of this hypothesis, table 

 4 is reconstructed by eliminating therefrom all hauls except those 

 made during June, 1909. The results are given in the following 

 table : 



