326 Natural History of British Zoophytes. 



Family II. TUBULARIAD^. 

 Polypes gemmiparous, the gemmules naked, pullulating from the 

 bases of the tentacula. 

 * No Polypidom. 

 2- CoRYNE. Polypes naked, the tentacula filiform. 



3. Hermia. Polypes tunicated, the tentacula with glandular tips. 



** A distinct polypidom, 



4. TuBULARiA. Polypes not retractile within cells: Polypidoms 

 fistular, simple or branched. 



Family III, SERTULARIAD^. 

 Polypes gemmiparous, the gemmules enclosed in external ovarian 

 persistent vesicles scattered on the polypidom. 

 * Polype-cells sessile. 



5. Thoa. Cells indistinct, tubular, the simple extremities of the 

 interwoven branchlets. 



6. Sertularia. Cells biserial, short, erect, the apertures everted. 



7. Thuiaria. Cells biserial, imbedded, the apertures looking for- 

 ward. 



8. Plumulauia. Cells uniserial ; the branchlets plumose or 

 pectinate. 



9. Antennularia. Cells uniserial ; the branchlets whorled. 



* Polype-cells on ringed stalks. 



10. Campanularia. Cells campanulate. 



I. HYDRAID.E. 

 I. Hydra, Linnaeus. 

 Character. — Polypes locomotive, single, naked, gelatinous, sub- 

 cylindrical, but very contractile, the mouth encircled with a single 

 series of granulous filiform tentacula. 



I. H. viRiDis, grass-green ; body cylindrical or insensibly nar- 

 rowed downwards ; tentacula Q — 10, sho7'ter than the body. (Fig. 

 Vol. i. p. 230.) 



Polypes verds, Trembley, Mem. 22, pi. 1. fig. 1 ; pi. 3, fig. 1 — 10 



Fresh-water Polypus, Trembley, in Phil. Trans. Abridg. viii. 623. Fol- 



kes, in ibid. 676. pi. 17, and pi. 18, fig. 1 — 3 Hydra viridis, Lin. 



Faun. Suec. 367, No. 1283, Lin. Syst. 1320. Mull. Verm. 1. ii. 13. 



Zool. Dan. prod. 230, No. 2783. Berk. Syn. i. 221. Ure's Rutherg. 232. 



Turt. Gmel. iv. 691. Turt. Br. Faun. 218. Lam. Anim. s. Vert. ii. 60. 



Stew. Elem. ii. 452. pi. 12, fig. 4, 3. Blumenbach's Man. 275. pi. 1, 



fig. 10. Bosc Vers ii. 274. Stark, l^Elem. ii. 443. Woodward, in Mag. 



Nat. Hist. iii. 349, fig. 89. Roget, Bridge w. Treat, i. 162, fig. 59, and 



176—8, fig, 73—76. Adams on the Microscope, 399, pi. 21, fig. 5. 



Cams, Comp. Anat. tab. l.fig. 1 H. viridissima, Pall, Elench. 31. 



