TRIBE I. ASTUTE A C E A. 209 



mellae not being so completely united together. In a vertical section, the 

 centre of the cell is subfilameritous, and the dissepiments on the sur- 

 faces of the lamellae are few, minutely delicate, almost horizontal and 

 nearly parallel. 



4. A. ORBICELLA PATULA. (Dana.) 



A. maxima, hemispherica, fusco-umbrina ; poly-pis 6-8'" latis, discispalr 

 lide radiateque griseis. Corallum cellulosum ; caliculis polygonis, 

 patulissime conicis aut subplanis, bene confertimque striatis et denticu- 

 latis ; cettis paululum excavatis, non coronatis, lamdlis incrassatis, spi- 

 noso-denticulatis : transverse secto, stellis multiradiatis, radiis crassis, 

 fere contiguis ; septis subcellulosis, cum paucis ceUulis angustis. 



Very large, hemispherical, dark-umber coloured ; polyps 6 to 8 lines 

 broad, with the disks radiated with pale gray. Corallum cellular; 

 calicles polygonal, flat conical, or nearly flat, evenly and crowdedly 

 striate without, and denticulate ; cells very shallow, not coronate ; 

 lamellae incrassate, spinoso-denticulate : in a transverse section, stars 

 many-rayed, rays thick and nearly contiguous; septa with a few 

 narrow cellules. 



Plate 10, fig. 14, part of a corallum with the animals unexpanded; 

 a, section showing outline of cells and ridges, and the dentation of the 

 lamellae ; b, an enlarged view of the same; c, d, vertical sections, natu- 

 ral size ; e, transverse section. 



The Feejee Islands. Exp. Exp. 



5. A. ORBICELLA CURTA. (Dana.) 



A. convexa ; poly pis prominulis, 3-4'" latis, lamellis 48. Corattum mi- 

 nutissime cellulosum; caliculis breviter conico-rotundatis, extus con- 

 fertim regulariterque striatis et subtiliter denticulatis ; cellis orbicu- 

 latis, 2$'" latis, subprofundis, intus subcoronatis ; lamellis fere 

 ceque exsertis, denticulatis : transverse secto, stellis fere multiradiatis, 

 cellulis parce subdivisis ; septis sapius minute cettulosis, cellulis lineatis 

 vel > -formibus. 



Convex ; polyps a little prominent, 3 to 4 lines broad, with 48 internal 



53 



