TRIBE I. ASTR^EACEA. 237 



dedalea. The cells appear open, owing to the unequal lamellae, and 

 are sometimes slightly coronate within. 



II. Collibus angustis, integris, apice subnudis ; larnettis viz exsertis sed vaZde in- 

 cequalibus. 



i 



39. ASTRJEA RIGIDA. (Dana.} 



A. subglobosa ; polypis 6-10'" latis. Corattum robustum ; cettis angulatis, 

 5'" latis et interdum 8-10'" elongatis, scepe lobatis, intus non coronatis; 

 collibus apice fere nudis, integris, tenuibus ; lamettis dentatis, valde 

 incequalibus, non confertis: transverse secto, septis solidis, 1'" crassis; 

 stellis vix multiradiatis, cellulis latis, parce decompositis. 



Subglobose; polyps 6 to 10 lines broad. Corallum firm; cells angular, 

 5 lines broad, and sometimes 8 to 10 long, often lobed, not coronate 

 within; ridges thin, entire, and naked at summit; lamellae dentate, 

 very unequal, not crowded : in a transverse section, septa solid or 

 with rarely a cellule, a line broad ; stars hardly many-rayed, cellules 

 large, and sparingly decompound. 



Plate 12, fig. 8 a, section of cell and ridges, showing profile of la- 

 mellae, natural size ; 8 b, a cell bisected ; 8 c, size and form of cells on 

 surface of corallum ; 8 d, transverse section, natural size. 



West Indies. 



The bare thin ridges, and distant unequal dentate lamellae, with the 

 large and often lobed cells, and thin but solid septa, are the prominent 

 characteristics of this common West India species. The bottom of 

 the cell is scarcely convoluted at centre, as the larger lamellae almost 

 meet. 



III. Collibus integris, aut subintegris ; lamellis bene regularibus ; cellis non coronatis ; 

 cellulis stellarum, corallo transversl secto, parcl aut non decompositis. 



40. ASTRJEA RETICULARIS. (Lamarck.) 



A. subglobosa. Corallum cellis angulatis, scepe oblongis et subflexuosis, 

 profundis, centra radiatis ; collibus subnudis, apice levibus. 



60 



