109 



DISCOPORA HISPIDA. Encrusting with a circum- 

 scribed base, calcareous, ridged or waved ; cells coalescent, 

 erect; apertures patulous, armed with one larger and two 

 smaller teeth. PI. xix., fig. 1. 



Discopora hispida, Fleming's Brit. An., p. 530. Johnston's 

 Brit. Zooph., p. 270, pi. 30, figs. 9, 11. 



Hab. On shells, stones, and corallines, from deep water, 

 common. Polperro, Fowey, Goran, &c. 



This very common species rarely exceeds an inch, but is 

 most commonly found about one-half or three-fourtlis of an 

 inch in diameter. It is calcareous, white, and from the 

 juxtaposition of the tubes, very solid. It is not a mero 

 incrustation, for it sometimes attains the thickness of half 

 an inch, but is most commonly about the tenth of an inch in 

 depth. The surface is most commonly uneven, either with 

 gently undulating ridges or papillary eminences ; and as the 

 tubes are so small that they cannot be distinctly seen with 

 the naked eye, it looks like a piece of white embossed 

 velvet. The tubes are irregular in size, erect, or but slightly 

 leaning, and the ridges or unevenness of the surface is 

 produced by their unequal growth. The apertures of the 

 tubes are patulous, and sometimes even and unarmed, though 

 most commonly armed with two or three stout conoidal 

 spines ; which is probably the manner in which the tubes 

 grow in length. 



CELLEPORIDJ3. 



Polypidoms calcareous, or membrano-calcareous, lobed, 

 ramous or crustaceous, formed of an aggregation of cells 

 disposed usually in quincunx; cells utricular, in justa-position 

 with contracted terminal apertures, often covered with an 

 operculum. 



CELLEPORA. 



Generic Character: Polypidoms calcareous, or n>embrano- 

 calcareous, cellular, lobed, ramons, formed of urceolate 

 cells heaped together, or arranged in a quincunx. Polypes 

 ascidian. 



CELLEPORA VITRINA. Encrusting, calcareous; cells 

 ovoid, very small, pearly, and irregularly arranged. 

 PI. xxii., fig. 1. 



Hab. On stones in moderately deep water, not rare. 

 Goran, Mr. Peach. Polperro. Mount's bay. 



This delicate and beautiful species, is very small ; it is 

 encrusting, circumscribed and rarely exceeding a quarter of 

 an inch in diameter. The cells are small, transparent, 

 vitreous or pearly in their appearance and very irregularly 



o 



