vni, a, 4 Smith: Fossil Invertebrate Fauna 283 



FORAMINIFERA 



NUMMULINID^ 



OPERCTJLINA d'Orbigny 



Shell typically complanate and planospiral with the whole of 

 the convolutions visible ; the earlier whorls more or less embrac- 

 ing; interseptal and marginal canals conspicuously developed. 

 Lower Cretaceous to Recent. (Chapman.) 



Operculina costata d'Orb. Plate XIII, fig. 1. 



Ann. sci. nat. (1826), 7, 281; Phil. Journ. Sci., Sec. D (1911), 6, 56. 



This form is found in great numbers in the limestone cliffs 

 along the Toledo road, Cebu, No. 277, about 3 kilometers west 

 of Naga on the banks of the Minanga River. The formation 

 is the upper limestone which dips gently to the southeast to 

 the sea. Specimens in the Bureau of Science collection vary 

 from 2 to 6 millimeters along the longest diameter. 



ORBITOUTES Lamarck 



Test discoidal, sometimes undulate or rarely sinous; growth 

 either spiral (nonembracing) just at the commencement, or 

 with one or more inflated, primordial chambers; subsequently 

 cyclical; chambers more or less regularly divided into chamber- 

 lets. Upper Cretaceous to Recent. (Chapman.) 



Orbitolites complanata Lam. (?) Plate XIII, figs. 2, 3, and 4. 

 Phil. Trans. Roy. Soc. (1856), 224, Pis. V-IX. 



The forms here shown apparently have the internal structure 

 of this species, certainly in external appearance they are quite 

 similar. They vary from 7 to 10 millimeters in diameter, and 

 are less than a millimeter in thickness. 



These were found by H. D. McCaskey some years ago on the 

 beach of Semirara Island. He reported that they occurred 

 there in great numbers, but was unable to say whether they 

 had weathered out of a limestone or were recent forms. I am 

 inclined to think they are very recent, although I am aware 

 that the species goes back to the Cretaceous. 



LEPEDOCYCLINA Giimbel 



Median plane composed of chamberlets arranged in regular 

 annuli around a distinct central chamber or chambers ; thickened 

 on either side by layers of flattened chamberlets more or less 



