60 DESCRIPTIOX OF THE PLATES. 



contractile (?) bands are seen passing from the inner side of the hjdrothecal valves to the body of 

 the hydranth. 

 Fig. 5. Portion of branch with front view of the hydrothecae ; magnified. 



Figs. 6, 7. Sertularella conica. 

 Fig. 6. Natural size. 

 Fig. 7. Portion magnified. 



Figs. 8-10. Sertuleurella amphorifera. 

 Fig. 8. Natural size. 



Fig. 9. Portion of a colony with gonangium ; magnified. 

 Fig. 1 0. Hydrotheca still further enlarged. 



PLATE XVI. 



Figs. 1, 2. Sertularia nieirginata. 

 Fig. 1. Natural size. 

 Fig. 2. Distal end of colony, magnified. 



Figs. 3, 4. Sertularia tumida. 

 Fig. 3. Natural size. 



Fig. 4. A portion, magnified. In one of the hydrothecae the hydranth and two opercular bands are still 

 visible. 



Figs. 5, 6. Sertularia tubitheca. 



Fig. 5. Entire colony, natural size. 

 Fig. 6. A portion, magnified. 



Figs. 7, 8. Sertularia exigua. 



Fig. 7. Colony growing on a seaweed ; natural size. 

 Fig. 8. A portion, magnified. 



Figs. 9, 10. Sertularia distans. 

 Fig. 9. Natural size. 

 Fig. 10. A portion, magnified. 



Figs. 11, 12. Thuiaria sertularioides. 

 Fig. 1 1 . Natural size. 

 Fig. 12. A portion, magnified. 



PLATE XVII. 



Figs. 1, 2. Thuiaria distans. 



Fig. 1 . Entire colony, natural size. 

 Fig. 2. A portion, magnified. 



Figs. 3-6. Thuiaria plumulifera. 



Fig. 3. Entire colony, natural size. 



Fig. 4. Portion of a branch with pinnae, magnified. 



Fig. 5. Hydrotheca more enlarged, lateral view. 



Fig. 6. Same, front view. 



PLATE XVIII. 



Figs. 1, 2. Plumularia filicula. 

 Fig. 1. Natural size. 

 Fig. 2. A portion with gonangia, magnified. 



Figs. 3, 4. Plumularia macrotheca. 



Fig. 3. Entire colony, natural size. 

 Fig. 4. A portion of a pinna, magnified. 



Figs. 5, 6. Plumularia attenuata. 

 Fig. 6. Natural size. 

 Fig. 6. Portion of stem with pinna, magnified. 



