TRIBE I. ASTRJ3ACEA. 291 



below very regular and about one-third of an inch deep; the corallum 

 is consequently three-fourths of an inch thick at middle. 



4. FUNGIA DISCUS. (Dana.) 



F. orbicularis, vix undulata, utrinque planiuscula. Corallum lamellis 

 tenuibus, incegualibus, denticulatis ; lamellis minimis intermediis cre- 

 nulatis, deinde integris et unidentibus (dente tentaculato), nunc pro- 

 minuttoribus et postea crenulatis aut denticulatis; subtus radiate 

 lamello-striatum, et spinosum, sed media striis obsoktis spinulisque 

 acutis et subtilissimis. 



Orbicular, a little undulate, on both sides nearly flat. Corallum with 

 thin lamellae, unequal, denticulate, the intermediate crenulate, then 

 entire, and bearing a single obtuse tooth, and afterwards becoming 

 one of the larger lamellae, and again crenulate or denticulate ; below 

 radiately lamello-striate and spinous, but about the middle, the striae 

 obsolete, and the spines acute and very minute. 



Plate 18, fig. 3, outline of lamella, above and below ; 3 a, one of the 

 intermediate lamella?, with the tentacular tooth. 



Tahiti, Society Islands. Exp. Exp. 



This species has the finely denticulate lamellae of the dentigera, 

 though a little coarser ; but the form is circular, the lamellae are not 

 flexuous, and the tentacular tooth is not, as in that species, prominent 

 above the general surface of the disk. The largest specimen is three 

 and three-fourths inches in diameter, and a half to two-thirds of an 

 inch thick. The spines below, near the margin, are about a line long, 

 and are often bent or aggregated ; but a central area, for nearly two 

 inches, is merely rough scabrous, without striaB. In the smaller spe- 

 cimen, the spinulous striae extend nearly to the centre, and are rather 

 crowded. It is near the agariciformis, small specimens of which it 

 resembles; but the lamellae are more crowded, and the intermediate 

 lamellae in that species, deep between the larger, are scarcely cre- 

 nulate. 



Stutchbury, Linn. Trans, vol. xvi. tab. 32, figs. 5, a, b. The figures appear to repre- 

 sent the above species. Fig. 1 may be a larger specimen of the same. 



