FORAMINIFERA OF THE PHILIPPINE AND ADJACENT SEAS. 383 

 OPERCULINA VENOSA (FIchtel and Moll), 



Nautilus venosus Fichtel and Moll, Test. Micr., 1798, p. 59, pi. 8, figs. e-h. 



Nummulites venosa Chapman, Proc. Zool. Soc. London, 1395, p. 47. 



Operculina venosa Chapman, Proc. Roy. Soc. Victoria, vol. 26, 1913, p. 173. 



Amphistegina cumingii Carpenter, Philos. Trana., 1859, p. 32, pi. 5, figs. 13-17. 



Nummulites cumingii H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 749, pi. 112, figs. 11-13; woodcut, fig. 22.— Baqcx, Proc. U. S. Nat. Mus., vol, 

 34, 1908, p. 166.— CusHMAN, Bull. 71, U. S. Nat. Mus., pt. 4, 1914, p. 39, pi. 14, 

 fig. 6. — Heron-Allen and Earland, Trans. Zool. Soc. London, vol. 20, 1915, 

 p. 739. 



There is a well-marked development of this species in certain 

 parts of the areas, especially in shallow warm waters among the 

 islands. At some stations it is very abundant and shows well the 

 development of the species. Brady's figui'es in the Challenger 

 report illustrate the early stages of this species, but the Philippine 

 specimens show later characters. These consist of a broadening 

 of the test and the development of a thin flangelike portion at the 

 periphery. The edge of the test is marked by the development of 

 a round carina, which is finely longitudinally striate, similar to what 

 is found in other species of Operculina. Many of the specimens 

 have the sutural lines broader than those figured by Brady, and of 

 a very clear shell material, through which the supplementary canals 

 can be seen as white lines. 



It has occurred at the following localities : China Sea, off southern 

 Luzon; Sulu Archipelago, near Basilan Island; vicinity of Jolo; 

 vicinity of Siasi; Tawi Tawi Group; off Romblon; off northern 

 Cebu; Sogod Bay, southern Leyte; and between Burias and Luzon, 



Brady records this species in 95 fathoms (174 meters) from the 

 Philippine Islands from dredgings of the CTiallenger. It seems to be 

 limited to the Indo-Pacific region. 



There are certain large specimens which seem to be microspheric, 

 in which the flangelike portion is greatly developed, which grow 

 to a size nearly 15 mm. in diameter. 



Chapman (1913, above) mentions that "in my ovm. cabinet there 

 is a series of tests of this form from the East Indian Archipelago, 

 wliich shows extreme modifications, ending with the typical Oper- 

 culina.^' Also, according to Chapman, '' Operculina venosa is found 

 on parts of the Australian coast at the present day, in the neigh- 

 borhood of the Great Barrier Reef." 



If this species, as it certainly seems, is an Operculina instead of a 

 species of Nummulites, it means that there are to-day no living 

 species of the latter genus which suddenly became so abundant in 

 the Eocene, As other genera of that period represented by com- 

 plex tests, such as Orthophragmina and Lepidocydina, have become 

 extinct, it is not strange that Nummulites may also have died out. 



