PLATE XXIV. 

 [Proc. Wash. Acad. Sci., Vol. II, PI. XX.] 



FIG. 5. Bugula purpurotincta Norman, frontal view. The two lower zoecia on 

 the left show the small size of the oecia (.) compared with that of the 

 embryo {emb.*) (#.) avicularium. 



5. An avicularium which had broken away from its zcecium ; peduncle 

 (ped.*), mandible (man.~), beak (), muscular apparatus (mus. app.). 



6. Dorsal view of the same, showing spine (s/5.) and avicularium (az>.) as 

 seen from the back, and the mode of bifurcation (bifur.}. 



7. Flustra lichenoides sp. nov. Frontal view, showing cecia (.) and vari- 

 ation in the number of flattened spines (y?. sp.). 



la. A single frond of the same, natural size. 



8. Dorsal surface of the same, showing the radical fibers (f.f.~) and their 

 mode of attachment to the zoecia. 



9. Membranipora sandalia sp. nov. Upper surface, representing a few 

 /oecia in the second stage. The aperture (/.) occupies the distal end 

 of the zoecium. Below it is the uncalcified area (^.) upon which an 

 avicularium will be formed, and toward which the calcareous thickenings 

 converge. 



9<z. One zcecium of the same near the edge of the colony. It is oblong in 

 shape and the aperture (^.) occupies the whole of the front. 



gb. A zoecium of the same, showing the beginnings of calcification (/.) 

 and (</.). The future aperture (a/.) is already laid off. 



[338] (*46) 



