14 



AKT. 6. R. B. NEWTON AND R. HOLLAND 



been a tendency, particularly among English authors, to make 

 this species include too great a variety of forms. There is for 

 instance a very considerable and constant difference between the 

 modern Operoulina complanata as figured in the Challenger Report 

 (Vol. IX, PI. CXII, figs. 3, 4, 5, and 8) and the 0. complanata 

 from the Burdigalian (=Langliian) of Bordeaux. The whole 

 genus needs careful revision. This, however, is not the occasion 

 for any attempt in that direction. 



Occurrence : Opereulina complanata in recent seas is es- 

 sentially a shallow water form and is met with only in tropical 

 and sub-tropical latitudes. As a fossil it is recorded from the 

 chalk of Maastricht and Minnesota, from the Eocene of Central 

 Europe and India, from the Miocene of Italy and of Muddy 

 Creek (Victoria) and in great profusion in the Burdigalian 

 ( = Langhian) of the Bordeaux area. The Riü-Kiü specimens are 

 from the "raised coral reefs" of Tokuno-shima and Okino-yerabu ; 

 and from a " 10 foot thick bed in raised coral reef" from Unten, 

 west coast of the Island of Okinawa. 



Opereulina complanata, (Defuanch) var granulosa, Leymerie. 

 (PI. Ill, figs. 4 and 5.) 



Opereulina granulosa, Leymerie : Mem. Soc. gcol. France, 

 1846. Ser. II, Vol. I, p. 359, PI. XIII, fig. 12 a, b. 



0. complanata, var. granulosa, II. B. Beady : Chall. Report, 

 1884. Vol. IX, p. 743, PI. CXII, figs. (3, 7, 9 and 10. 



This species is exceedingly numerous in the dark earthy 

 looking material from Itoman, S. Okinawa, which is described as 

 " overlaid discordantly by the raised coral reefs." Besides the 



