f 10 



arranged. The apertures are very minute, and terminal, and 

 cannot readily be seen even with a lens. 



PUMICE-STONE CORALLINE. C. Pumicosa. En- 

 crusting, cells ovoid or sub-orbicular, generally heaped 

 irregularly together, when young arranged in a quincunx ; 

 apertures round, armed with three marginal teeth. Pi. xx., 

 fig. 3. 



Porous eschara, Ellis' Coral., p. 75, pi. 27, fig. f F., pi. 30, 

 fig. d, D. Cellepora pumicosa, Turton's Lin,, vol, 4, p. 640. 

 Stewart's Elem., vol. 2, p. 428, pi. 12, fig. 16, 17, copied 

 from Ellis. Fleming's Brit. An., p. 532. Templeton in 

 Mag. Nat. Hist., vol. 9, p. 469. Johnston's Brit. Zooph., 

 p. 273, pi. 32, figs. 1, 2, 3. Bellamy's Nat. Hist, of South 

 Devon. Millepora pumicosa, Ellis and Solander's Zooph., 

 p. 135. Turton's Lin., vol. 4, p. 639. Stewart's Elem., 

 vol. 2, p. 428. Fluslra bullata, Ellis and Solander's Zooph., 

 p. 16. Stewart's Elem., vol. 2, p. 436. Turton's Lin., vol. 4, 

 p. 664. 



Hab. On stones, shells, and roots of sea-weed, common. 

 Polperro. 



This very common species presents itself under a variety 

 of aspects, depending on the character of the substance it 

 incrusts. As it is most commonly found on Corallines, it 

 generally resembles globular pieces of pumice-stone, from 

 whence it derives its name. When living it is of an orange 

 red colour, and sometimes pinkish ; but when seen in collec- 

 tions, it is of a light dusky brown colour. It is calcareous, 

 porous, friable, and encrusting. The cells are ovato-globose, 

 round, or egg-shaped, depending on the figure of the substance 

 it encrusts. The apertures of the cells are armed with three 

 marginal teeth, which, from being easily destroyed, are not 

 always to be found. In young specimens, encrusting a plain 

 surface, the cells are always egg-shaped, and regularly ar- 

 ranged in a quincunx ; but as age advances, the first layer of 

 cells becomes irregularly covered with others of a newer for- 

 mation. As this irregular accumulation of cells is constantly 

 going on, the porous friable mass, commonly seen, is formed. 

 There is a variety sometimes found on shells, which, when 

 living, has a pearly appearance, which seems to be the Flustra 

 bullata of Lincaeus and Ellis. 



BRANCHED CELLEPORE. C. R amnio sa. Polypidom 

 calcareous, dichotomously branched ; the branches cylin- 

 drical, rough, and obtuse; cells irregularly distributed; 

 apertures armed with a spine on the outer lip. 



Cellepora ramulosa, Turton's Lin., vol. 4, p. 640. Flem- 

 ing's Brit. An., p. 532, no. 131. Johnston's Brit. Zooph., 

 p. 274, pi. 32, figs. 4 and 5. 



