l6o CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



But in examining the character of the variations presented 

 by the three famihes from a systematic point of view, even 

 more important conclusions may be drawn. Although as 

 regards described species they may be applied to six species 

 only, as regards the kind of color characters that can be 

 admitted to have any value as diagnostic characters they 

 have a much wider bearing. Thus none of the following 

 color characters are of any value in differentiating species 

 or even varieties: — 



/. Color of the ampullce, for it varies much in the same 

 colony at different times and in different regions at the 

 same time. Thus, in the colony whose zooids are repre- 

 sented in figs. 26 and 27 the ampullse near the green zooid 

 were of the same green as the zooid, while those near the 

 other were transparent with a very light green tinge. The 

 color of the ampullae varies regularly with the age of the 

 colony. At first they are transparent, then light grayish, 

 yellowish, or greenish, while in old age and unfavorable 

 conditions dark browns and black usually predominate. 

 The dark pigment, however, is often mixed with opaque 

 white, which may supplant the yellow pigment present at 

 an earlier period. 



2. The general tone, or ground-color, of the zooids is of 

 no value, for it may vary in different parts of the same 

 colony (figs. 26, 27) or in the colony at different times 

 (figs. II, 12, 17-21), or still more in different colonies of 

 the same family. 



J. The presence of conspicuous markings, such as the 

 double dorsal bands, light colored lower lip of the cloacal 

 orifice, and light coating covering the posterior part of the 

 zooid is of no value, for these may be conspicuousl}' devel- 

 oped, entirely absent, or partially developed in colonies 

 of the same family (Family I, figs. 1-15; Family II, 

 figs. 16-23). 



/f.. The color or shape of such markings is valueless, for 

 they vary in the same colony even at the same time. The 



