38. Cups well separated, with rows of small knobs marking 

 boundary lines. Septa only protrude slightly (Plate 1) 



!Madracis decacUs (Lyman) 

 Cups fairly close to each other. Septal protrude above surface 



Stephanocoenia micheUni 

 Edwards and Haime 



39. Cups rarely exceed 2.5 mm in width 40. 



Cups over 2.5 mm in width 44. 



40. Coral not porous. Cups separated by about half their width 



Sotenasirea hournoni Edwards 

 and Haime 

 STAR CORAL 

 Coral porous. Cups not separated but joined by common wall 41 . 



41. Cups 2.5 mm wide. Septa protrude above surface of coral 



Astrocoenia pectinata Pourtales 

 RARE STAR CORAL 

 Cups under 2 mm wide. Septa do not protrude beyond sur- 

 face of coral 42. 



42. Cups 0.9 to 1.2 mm wide 



Porites branneri Rathbun 

 POROUS CORAL 

 Cups 1.2 to 1.5 mm wide 43. 



43. Shallow cups with thin wall less than 0.4 mm (Plate 11) 



Porites astreoides Lamarck 

 POROUS CORAL 

 Deeper cups with wall about 0.4 mm 



Porites verriUi Rehberg 

 BRAZILIAN POROUS CORAL 



44. Cups circular and over 6 mm in diameter 45. 



Cups do not exceed 6 mm in diameter 47. 



45. Cups closely touching, forming double walls 



7avia tephtophyUa Verrill 

 BRAZILIAN CORAL 

 Cups up to 5 mm apart. Never form double walls (Plate 27) 46. 



46. Coral between cups Mistered in appearance 



Tdontastrea hraziliana Verrill 

 BRAZILIAN STAR CORAL 



7i 



