574 



THE AMERICAN NATUBALIST [Vol. LI 



water, but no e%-idence of this relative to *S^. democratica is re- 

 corded in the literature. 



During June and July, 1908 and 1909, thirty surface-net hauls 

 were made in the vicinity of San Diego when the temperature of 

 the water was between 15°.9 and 18°.3 C, and forty-six when it 

 was between 18°. 4 and 20°. 8 C. Solitary forms were captured 

 in greater numbers per unit volume of water filtered from the 

 warmer water, and zooids from the colder water. But one or 

 more of both solitary forms and zooids were captured from a 

 larger per cent, of these unit volumes in the colder than in the 

 warmer water. This is better shown by the following table : 



15.9-18.3 3(1 67 92 529 92 



18.4- 20.8 l*iO 73 127 80_ 



These data show that, while zooids occurred in greatest num- 

 bers in the places they frequented the most as would be expected, 

 solitary forms occurred in greatest numbers in the places they 

 frequented the least, or, to state it differently, they were found 

 most often where they occurred in smallest numbers. What 

 does this apparent paradox mean ? 



Believing that these relations must have been con.sequeut upon 

 a freak result of chance or random sampling, and discovering 

 that only 9 of the 30 cold-water hauls were made during the night 

 (6 p.ii.-6 A.M.) while 33 of the 46 warm-water hauls were made 

 at night, the day hauls and r ^1 1 I 1 e si^ia rated, and the 

 data concerning each were retabulated uitli respect to the same 

 two groups of temperatures. The results are given in the table 

 on p. 575. 



Be it noted that, although the magnitudes of the differences 

 vary, the directions of the differences are exactly the same as 

 revealed by the data in the above table, i. e., solitary forms are 

 most abundant and least freriueiit in the warmer water, while 

 zooids are most a])unilaiit and most frequent in the cnhler water. 



Still being in tl\e position uf an unheliever. the data were re- 



