191''^] Michael: Behavior of Salpa dcmocratica 279 



forms in each of a number of long protruding chains? Do the facts 

 not suggest that, if retabulated again relative to temperature groups 

 of still smaller range, the data may reveal an excess in abundance of 

 solitary forms in the coldest water over that in next coldest 1 Accord- 

 ingly, table 14 is supplied, in which the data are retabulated with 

 respect to six temperature groups each having a range of 0?8C. 



Once again is each of the four conditions deduced from the loco- 

 motion theory evident, though not so strikingly, perhaps, as in the fore- 

 going tables : 



1. The frequencies of the two generations are identical relative to 

 the lowest, second lowest, third lowest, and second highest temperature 

 groups, and they are parallel throughout. The frequency of both 

 decreases as the temperature increases from its lowest to its middle 

 value (18?3C to 19?0C), and then increases as the temperature 

 increases to its highest value. 



2. Both generations appear more frequently in the coldest than 

 in the warmest water, in the second coldest than in the second warmest 

 water, and in the third coldest than in the third warmest water. 



3. The abundance of aggregate forms, while more erratic than 

 shown by the foregoing tables, parallels in general the frequency, 

 being greatest (1195 per hour) in the coldest water and least (59 per 

 hour) in water having a temperature between 18?3C and 19?0C. 



4. Except that slightly less, instead of more, than 81 solitary forms 

 per hour were obtained when the temperature was between 18?3C 

 and 19?0C, they increase in abundance as the temperature increases 

 from next to its lowest to its highest value. Is it not a significant cor- 



