192 MADREPORARIA. 
194, Porites Christmas Island (2. (P. Natalis secunda.) 
[Sea Cliff, Rocky Point, North Coast * (Pleistocene), coll. C.W. Andrews; British Museum. ] 
Syn. Porites aff. lutea M.-E. & H.” Gregory (partim), A Monograph of Christmas Island (1900) 
p. 222. 
Description.—The corallum was massive; the calicles about 1 mm. across. The walls 
were irregularly reticular, about 0°5 mm. thick. The septal or intra-calicular skeleton had 
largely lost its primitive radial symmetry and become an open reticulum continuous with that 
of the walls. The fossa was frequently open and surrounded by a ring of tissue, but sometimes 
closed by a columellar tangle, that is by strands of the intra-calicular network. 
The vertical section shows the polyp cavities running continuously through the mass ; the 
trabecule are, nevertheless, not very pronounced, though more definitely continuous than the 
horizontal elements; the meshes are large and often rectangular, and the mass consequently 
very porous. 
This is a very well preserved fragment, much weathered, and without any of the original 
surface preserved. The directions of the polyp cavities show considerable complexity of growth. 
The stock appears in life to have been rolled over. This should be compared with P. Christmas 
Island 4. The rectangular filamentous meshwork of the section is replaced in that form by a 
flaky reticulum. : 
a, No. 161. Geol. Dept. R. 3742. 
Under this same heading I would include the fossil 
No. 132. 
[Second Inland Cliff, East Coast (altitude 550 feet), coll. C. W. Andrews ; British Museum. | 
Syn. Porites belli (pars) Gregory, |. c. 
This is a very altered fragment, and the details are not easy to make out. But the walls 
are certainly reticular, as is also the intra-calicular skeleton, the latter losing thereby the 
sharpness of its radial symmetry. These are both important points allying it with a. 
The fragment has been cut in half, and there is a microscopic slide. 
b. Geol. Dept. R. 3744. 
* This information is taken from Dr. Gregory’s paper, p. 222. 
