angular. Septa 3 6 to 40, jour unecjual cycles, jtrst 

 two very distinct from others, last cycle incomplete. 

 Larger septa slightly exsert, seirulate, inner edges per- 

 pendicular. Columella small and papillose. 



1 1 . Siderastrea siderea (Ellis and Solander) , (Plate 7) . 

 Described by Vaughan (1919), page 443. 

 Larger masses than S. radians, sometimes over 2 feet. 



Cups 4 to 5 mm across. Septal margins slope more 

 than S. radians so that cup is larger and shallower. 

 Septa 50 to 60. Common on Florida reef, Bahamas, 

 West Indies and Bermuda. 



^hemispherical masses up to 2 or 3 feet in diameter. 

 Calices up to 4-5 mm sometimes 6 mm in diameter, 

 wall slightly raised. Jhree or 4 rows of synapticulae 

 on each side of wall between septa. Septa in five cycles, 

 last cycle incomplete. Less difference in size of septa 

 than S. radians. Septal margins more sloping and more 

 finely dentate. Columella small. 



12. Siderastrea stellata Verrill. 



Described by Vaughan (1919), page 440. 



Similar to S. radians, but cups deeper and more ir- 

 regular. Found only in Brazil, where it is widely dis- 

 tributed on the Abrolhos reef and at Bahia. 



Calices irregular 2-3 mm wide and up to 6 mm or 

 more long. Cerioid. 7our cycles of septa, last cycle 

 incomplete. Inner margins of septa very steep, more 

 coarsely dentate than S. radians. Columella finely 

 papillate and less developed than in S. radians. 



13. Porites astreoides Lamarck, (Plate 11). 

 Described by Verrill (1902) , page 160. 



Usually yellowish brown in color. Forms rounded 

 masses, covered with small bumps and growing to up 

 to more than 2 feet. Cups from 1.25 to 1.50 mm in 



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