92 
ZOOPHYTA HYDROIDA, 
Family III. 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. 
6. 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. 
