TRIBE I. ASTR^EACEA. 231 



and finely denticulate, and the cellules of the star in a transverse sec- 

 tion are but sparingly decompound. In a vertical section the lamella? 

 and lines of cells are irregularly curving. 



31. ASTR.EA TENELLA. (Dana.} 



A. hemispherica, pohjpis 3-5'" latis. Corallum percettulosum, fere spon- 



giosum ; caliculis polygonatis, scepe oblongis : transverse secto, stellis 



l-l(j-radiatis, radiis tenuissimis, cettulis grandibus circum centrum 



porosum eleganter dispositis, et margine aliis parvulis scepius biseri- 



atis ; septis angustissime filiformibus. 



Hemispherical; polyps 3 to 5 lines broad. Corallum very light cel- 

 lular ; calicles polygonal often oblong ; in a transverse section, stars 

 very slenderly 14 to 16 rayed, with large radiate cellules around the 

 porous centre, and at the margin other small cellules in one or two 

 series; septa delicately filiform. 



Plate 13, fig. 1, transverse section of corallum, slightly enlarged 

 (about a sixth); 1 b, vertical section of same, natural size. 



Wake's Island, Pacific Ocean. Exp. Exp. 



This coral was met with only in worn specimens. It is very light 

 and cellular, and extremely neat in its stars and texture. It appears 

 to have simple stars about a fourth of an inch in diameter, with septa 

 a line or more wide, consisting of three or four series of minute sub- 

 quadrate cellules; but the cellules properly belong to the stars, and 

 the true septum is a delicate line. In a vertical section the trans- 

 verse dissepiments are seen to be quite oblique and not very much 

 crowded, and from this the appearance above described proceeds. 

 The porous centre of the star is about a line broad. 



32. ASTR^EA MAGNIFICA. (Blainvilk.) 



A. conveza, subhemispherica. Corallum percettulosum ; cellis scepe elon- 

 gatis et paulo flexuosis, 2-3'" latis et interdum 8'" longis, angulatis, 

 profundis, intus breviter coronatis; collibus angustis (viz 1'") integris 

 obtusis, perpendicularibus ; lamellis bene cequalibus, subtiliter ekgan- 



