Fossil Corals. 



217 



The Christmas Island specimens differ from Milne Edwards 

 and Haime's diagnosis in three respects, which appear to me to be 

 worthy of at least varietal recognition. 



Var. columnata/ nov. 



The variety differs from the typical form of the species by 

 ha\ing deep open calices ; the columella is very large ; and the 

 tertiarj' septa are not united to the secondary' septa. 



The'diameter of the corallites is from 1 1-13 mm, ; the diameter 

 of the columella is about 5 mm. ; and there are about 3-^- cycles 

 •of septa. 



Distrihition. 

 a. Eecent : 



Locality of the type unknown. 

 h. Fossil : 



Christmas Island. IN'o. 322. Limestones of the sea- 

 cliff scries, mouth of Sidney's Dale. 

 Figure. — Pig. 3. Part of a transverse section, X H dia. 



Fig. 3. 



Orbicella prseheliopora, sp.n. 



Diagnosis. — Corallum massive : external characters unknown. 

 Corallites of medium size, being from 4-5 mm. in diameter, circular, 

 and separated by from 1 to 2 mm. Columella very spongy, but 

 large, being from 1-1-5 mm. in clia. Septa irregular; in some 

 sectors of a corallite there may be representatives of an incomplete 

 sixth order; whereas in the adjacent sector the septa of the fourth 

 order are rudimentary and barely recognizable. The primaiy and 



Golumnatus, furmshed Tvith a column, in reference to the large columella. 



