ERYLUS SOLLASII. 



287 



merely due to differences in the amount of light to which the cUfferent speci- 

 mens were exposed during life. I am therefore inclined to consider these 

 differences as direct individual adaptations of the simplest kind to which no 

 systematic importance whatever can be attached. 



The chief differences in the spiculation of the six forms is shown in the 

 following tabular view of the averages of the three largest observed of the most 

 important spicule dimensions and of the character of the triaene-cladomes and 

 aspidasters. 



This table shows that in race I, form A, all the triaene-clades are simple; 

 and the rhabd megascleres shorter and thinner, the microrhabds longer and 

 thicker, and the triaene-cladomes smaller than in any of the others. In race I, 



