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



These color markings are : — 



1. The dorsal double bands, extending from cloacal 

 to branchial orifice. These bands were found only in 

 Family II (figs. 16-23) and Family III (figs. 24, 25). 

 The mothers of both families had them well developed. 

 In Family II six of the young colonies became old enough 

 to acquire the adult colors; and of these, two (figs. 17, 19,^ 

 23) had the dorsal bands, two had no trace of them, look- 

 ing like the upper colony in fig. 23, and two had the 

 anterior half of the bands developed (fig. 22). 



2. The light-colored coating on the cloacal halves of 

 the zooids (figs. 3, 8, 14). It always extends all the way 

 from cloacal to branchial orifice, but sometimes extends 

 squarely across the zooid (fig. 8) and sometimes is drawn 

 out into a point which touches the branchial orifice. In 

 the case of this marking the discontinuity is not so striking 

 as in the previous one; perhaps because there were a 

 larger number of colonies to examine. It was encountered 

 only in Family I (figs. 1-15). Seventeen colonies were 

 examined, and in only two cases were transitions from 

 colonies possessing the coating to those without it encoun- 

 tered. In one case (figs. 11, 12) the coating was only 

 partially developed; in fact, there is a question whether 

 the marking represented a coating or the two dorsal bands. 

 But this imperfect development was quite constant during 

 the prime of the colony. The other exception was the 

 colony represented in fig. 8. When this colony was in its 

 most flourishing condition its zooids sometimes had the 

 coating as in the figure, sometimes had none, and some- 

 times presented a streaked intermediate condition. With 

 these two exceptions, the variation was discontinuous. The 

 contrast between the colonies having the coating and those 

 without it was greater than appears in the figures, for it 

 frequently happened that two or more colonies would be 

 exactly alike except for the presence in one of them of 



iThe condition of the dorsal bands in the other figures of this same colony (figs. 

 18, 20, 21) cannot well be considered as transitions to another type, for they do not 

 represent the usual appearance at that time, but only the extremes represented by a 

 few zooids. 



