172: PHYLUM C@LENTERA. 
Fic. 89.—Hydroids.—After Hincks. 
I, Tubularia, II A. Piece of Sertularia. II B. A fragment enlarged, 
showing sessile hydrothece (/7.) on both. sides of the twigs. IIT A. 
Plumularia. III B. A fragment enlarged, showing hydrothece (H.) 
on one side of each twig, an epillary penothees (G.) and minute nemato- 
phores. IVA. Campanularian. B. A fragment enlarged, showing 
stalked hydrothece (H.), a gonotheca (G.); C., the coenenchyma; P., 
the perisarc ; S., a stalk. 
