l86 CALIFORNIA ACADEMY OF SCIENCES. [Proc 3D Ser. 



EXPLANATION OF PLATE XVIL 



All the figures are drawn from living colonies growing on glass slides. 

 The back-ground upon which the vessel containing the slide was placed was 

 in all cases the same as the back -ground of the figures. The magnification 

 is in all cases 10. 



The drawings are everywhere as accurate as they could be made. The 

 adjacent zooids always occupied the position represented in a single system, 

 and were never selected from different places in the same colony. The 

 branchial and cloacal orifices were open in the majority of cases. Within the 

 branchial siphon the endostyle can usually be seen, and occasionally the 

 branchial sac and tentacles were visible. The smaller bodies at the sides 

 of the zooids are always buds where not specially referred to. Each figure 

 represents the average color of the colony unless especially excepted. 



Figs. 1-15 represent members of Family /, derived from the larvce ex- 

 truded by a single mother colony ; each represents a different 

 colony except as specified below. 



Figs. 5, 6, 7. Two zooids from the same colony drawn on August 16, 

 17 and 18 respectively. The protuberances on the sides of the zooids in 

 fig. 5 are not buds. 



Fig. 8. The salmon colored spots are the ova showing through. 



Figs. 1 1-12. Representative zooids of the same colony, drawn on June 27 

 and July 14. 



Figs. 16-23 represent members of Family II. 



Figs, i'j-21 represent zooids from different parts of the same colony, 

 drawn at various tifnes. 



Fig. 16. The mother colony of Family. II, a few weeks before death. 



Fig. 17. Average appearance of zooids on June 15. 



Fig. 18. Color of about one-third of the zooids, July 25. 



Fig. 19. Color of about two-thirds of the zooids, July 27. 



Fig. 20. Zooids from the growing edge. Most of the zooids had complete 



double bands, August 4. 

 Fig. 21. Zooids from the growing edge. Most of the zooids have more 



white pigment, forming more complete double bands; but they 



also have the other markings represented in the figure. 

 Fig. 23. A single system containing zooids derived from two different 



colonies. None of the zooids of the colonies here represented 



are figured elsewhere. 

 Fig. 24. Mother colony of colony represented in next figure. 

 Fig. 25. Offspring of colony in fig. 24. 



Fig. 26. An average zooid from the middle of a collected colony. 

 Fig. 27. An average zooid from Hao. growing edge of the same colony. 



ABBREVIATIONS USED. 

 A. — Ampullae. 



O. — Old zooid undergoing degeneration . 

 Y. — Young zooid. 



