i8o 



CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Morphological 

 Characters. 



Physiological 

 Characters. 



1. Separate localized exist- 

 ence. 



2. Investment of the zooids 

 in a common test. 



3. Presence of a common 

 vascular system. 



I. The quality determining 

 whether the colony shall 

 fuse or compete with a 

 neighboring one. 



3. The coordination in the 

 growth and reproduction 

 of the zooids. 



On the other hand, three of the characters are intimately 

 associated with the zooids, and hence these characters of 

 the colony must be considered as due to the summation of 

 the characters resident within the zooids; these are: — 



Morphological 

 CJfaracters. 



Physio logica I 

 Characters. 



Characteristic and com- 

 paratively constant colors 

 of the zooids. 



The force regulating the 

 formation and size of the 

 systems (?). 



The character causing 

 the short life of the 

 zooids (?). 



The answer, then, to the second question, concerning the 

 individuality of the Botryllus colony, is that on the whole it 

 must he considered as a single individual and not as an 

 aggregation of zooids, although certain of the individual 

 characters differentiating one colony from another must 

 be considered, merely as the summation of these same 

 characters resident within the zooids. 



