PHYLUM CCELENTERA. 



FIG. 89. Hydroids. After Hincks. 



I. Tnbularia. II A. Piece of Sertularia. II B. A fragment enlarged, 

 showing sessile hydrothecae (//.) on both sides of the twigs. Ill A. 

 Pltimularia. Ill B. A fragment enlarged, showing hydrothecse (H.) 

 on one side of each twig, an axillary gonotheca (.) and minute nemato- 

 phores. IV A. Campanularian. IV B. A fragment enlarged, showing 

 stalked hydrothecae (//.), a gonotheca (G.)', C., the crcnenchyma ; P^ 

 the perisarc ; S., a stalk. 



