Fossil Corah. 



21' 



The Christmas Island specimens differ from Milne Edwards 

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

 worthy of at least varietal recognition. 



Yar. columnata,^ nov. 



The variety differs from the typical form of the species hy 

 having 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 11-13 mm. ; the diameter 

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

 of septa. 

 Distribution. 

 a. E-ecent : 



Locality of the type unknown. 

 I. Fossil : 



Christmas Island, '^o. 322. Limestones of the sea- 

 cliff series, mouth of Sidney's Dale. 

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



Fig. 3. 



Orbicella prseheliopora, sp.n. 



Diagnosis. — Corallum massive : external characters unknown. 

 Corallites of medium size, being fi'om 4-5 mm. in diameter, circulai', 

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

 large, being from 1-1 "5 mm. in dia. 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 primary and 



Golumnatus, furnished with a column, in reference to the large columella. 



