318 ESCHAMD^. 



DiscoPORA VERRUCOSA, Gray, B.M. Ead. 126. 



??EscnARA VERRUCOSA, |3^, formiB costatas, Smitt, Q5fv. K. Vet.-Akad. Forh. 

 1867, Bihang, 22 and 142, pi. xxvi. fig. 135. 



Zoopcia large, broad-ovate, or occasionally rhombic, bor- 

 dered by raised lines, depressed below, elevated above, 

 the front wall rising into a broad and prominent 

 umbo a little below the orifice, which is often produced 

 into a kind of rostrum ; surface smooth or subgranular, 

 strongly areolated round the margin, and traversed by 

 radiating ridges ; orifice ample, suborbicular, or often 

 subquadrangular, arched above, the lower margin almost 

 straight, slightly curved inward in the middle ; usually 

 an avicularium, with a semicircular mandible, on the 

 inner side of the umbo. Ocecia semicircular, punc- 

 tured in front, and surrounded by a thickened spinous 

 border or crest. 



Polypide red, with 20 to 30 tentacles. 



Colonies forming large crusts, of a fine rose-red colour, 

 spreading irregularly. 



Range of Variation. This species, under different con- 

 ditions, exhibits a great variety of aspect. In the littoral 

 form the walls of the cells are very slightly calcified ; they 

 are generally thin and smooth, or merely subgranular, 

 and round the edge of the colony are often almost mem- 

 branous. In some cases they appear as if covered with 

 a thin, rather glossy, papyraceous material; the areola- 

 tions round the margin are obscure ; and there is a total 

 absence of the radiating ridges. In the littoral variety 

 the latter are always comparatively slender, and fre- 

 quently extend for a short distance only from the margin. 

 In young specimens the cells are hyaline and shining, 

 the surface is perfectly smooth and of a bluish-grey tint, 

 a white line runs round the cell a little above the base, 

 inclosing the marginal areolae, while the central portion 

 is traversed by delicate longitudinal ridges and frequently 



