PLATE 41.— Polypi and Polyzoa. 



Figure 



1. Areolar tissue of sea-anemone (Actinia mesembryanthemum); with spicula, cells, 



and fibre-cells. 



2. Spicula from the same. 



3. Alcyonella stagnorum. a, entire polyzoary ; b, perpendicular section, showing 



tubes and ova ; c, back view of polype with tentacles ; d, ova. 



4. Campanularia volubilis. a, growing upon a piece of Plumularia falcata ; 



b, portion of polypidom more magnified ; 4 c, cell of Laomedea dichotoma 

 with ova ; d, medusa-germ or gonozoid of Clytia. 



5. Canda (Cellular ia) reptans, portion of polypidom of. 5 a, Bicellaria (Cellu- 



laria) ciliata ; 5 b, the same more magnified, * a bird's-head process ; 5 c, pos- 

 terior view of a cell of Canda reptans, with its appendices ; 5 d, three appen- 

 dices to a cell of the same ; 5 e, polype expanded; 5/, perforated septum. 



6. Corallium rubrum; axis with polypiferous crust. 



7. Spicula from the crust. 



8. a, transverse section of the axis of red coral, from the furrowed exterior towards 



the centre ; b, longitudinal section. 



9. Body of Cristatella mucedo. 



10. Ova of the same, seen from above. 



11. Branch of Sertularia rugosa. 



12. Portion of the same, magnified, with cells a, and vesicles b. 



13. Sertularia purnila. 



14. Portion of the same, magnified, a, cell; b, vesicle. 



15. Sertularia operculata. 



16. Portion of the same, magnified, a, cells ; b, vesicles. 



17. Lepralia variolosa. 



18. Membranipora pilosa. 18*, polypes protruding from the cells ; 18 a, cell ; 



b, valve tbrough which the ciliated tentacles c protrude ; d, oesophagus ; e, 

 pouch containing the stomach, liver, &c. ; /, place of gyration of particles in 

 intestine ; g, rectum. 



19. Piece of Flustra carbasea. 



20. Cells of the same, magnified. 



21. Hydra viridis, attached to Lemna. 



22. Stinging orgaus of Hydra vulgaris, a, capsule with the spines and filament 



enclosed ; b, capsule with the spines and filament protruded ; c, very minute 

 capsules ; d, capsule imbedded in a globule of the sarcodic substance of the 

 body. 



23. Tentacle of Hydra viridis. a, stinging organs in situ. 



24. Hydra viridis, with spermatic capsules a, and ovarian capsule b. 



25. Ovum of Hydra, with the young polype bursting through its shell. 



26. Bird's-head processes of Flustra avicularis. 



27. Spiculum of a Gorgonia. 



28. Spicula of Alcyonium digitatum. 



29. Globules of sarcodic substance of a crushed Hydra viridis. a, one containing a 



small vacuole and several green granules ; the latter are more magnified below ; 

 b, a globule greatly distended by the formation of a large vacuole. 



30. Tubulipora, with a polype protruding from a cell. 



