FOEAMINIFERA OF THE PHTLrPPIISrE AND ADJACENT SEAS. 485 



As a rule the chamber walls of 0. marginalis are thinner than in the 

 other species giving a characteristic bluish tinge to the test not usually 

 noticed in either of the other species. 



0. marginalis was less common than 0. duplex, but more so than 

 O. complanata except in very shallow water. It is abundant at many 

 of the stations usually in shallow water but in a few cases found at 

 more than 500 fathoms (914 meters). 



It seems to be most common among the islands rather than on the 

 open outer shores. To the southward it was found between Gillolo 

 and Kayo a. 



Orbitolites marginalis — Material examined. 



ORBITOLITES OUPLKX Carpenter. 



Orbitolites, duplex tj-pe Carpenter, Philos. Trans., 185G, p. 120, pi. 5, fg. 10; 



pi. 9, fig. 10. 

 Orbitolites duplex Carpenter, Rep. Challenger, "Orbitolites," 1883, p. 25, pi. 3, 



figs. 8-14; pi. 4, figs. 6-10; pi. 5, figs. 1-10.— H. B. Brady, Rep. Voy. Challenger, 



Zoologj^ vol. 9, 1884, p. 216, pi. 16, fig. 7.— Cushman, Bull. 71, U. S. Nat. Mus., 



pt. 6, 1916, p. 94, pi. 38, figs. 3, 4; pi. 39, fig. 1. 



This species is represented at a greater number of stations than 

 either of the others as far as our material shows. Depths range from 

 10 to 732 fathoms (18 to 1,339 meters). It is most common in fairly 

 shallow water among the islands of the iVrchipelago, but occurred in 

 Darvel and Sibuko Bays, Borneo. Most of the stations were at depths 



