92 ZOOPHYTA HYDKOIDA. 



Family HI- SERTULARIADiE. 



Polypes gemmiparous, the gemmules enclosed in external ovarian 

 persistent vesicles scattered on the polypidom. 

 * Polype-cells sessile. 

 5. Thoa. Cells indistinct, tubular or campanulate, alternate. 

 G. Sertularia. Cells biserial, vasiform, short, erect, the aper- 

 tures everted. 



7. Thuiaria. Cells biserial, tubular-conical, imbedded, the aper- 

 tures looking- forward. 



8. Plumularia, Cells uniserial ; the branchlets plumose or pec- 

 tinate. 



9. Antennularia. Cells uniserial ; the branchlets whorled. 



** Polype-cells on ringed stalks. 



10. Laomedea. Cells from a thickened joint of the stem, alter- 

 nate, campanulate. 



11. Campanularia. Cells continuous with the stem, irregular 



or whorled, campanulate. 



Fig. 10. 



