GEOLOGY AND PALEONTOLOGY OP THE CANAL ZONE. 75 



in the last formed coil; sutures slightly curved, depressed; wall 

 smooth, distinctly punctate; septal lines with regularly arranged, 

 narrow bridging ; aperture a narrow semicircular opening at the base 

 of the apertural face of the chamber, showing occasionally traces of 

 division into a series of smaller openings. 



Diameter 0.50 to 0.65 mm. Cat Nos. 324685-7, U.S.N.M. 



Specimens were obtained in the Culebra formation, IT.S.G.S. No. 

 6020a, opposite Las Cascadas, in lowest fossiliferous bed, third bed 

 below lowest limestone. These were very largely glauconitic, and 

 of the form figured in 4«, b. The species was also found in the 

 Gatun formation, U.S.G.S. No. 6029a, one-fourth to one-half mile 

 north of Camp Cotton, relocated line of the Panama Railroad, in 

 the softer sandy marls at the base of the section. The form figured 

 in 3a, h, is from a Pleistocene deposit at U.S.G.S. No. 5850, loose 

 shells and marl from near Mount Hope, one-fourth mile from present 

 beach, 6 to 8 feet above high tide. 



POLYSTOMELLA SAGEA d'Orbigny. 



Plate 26, figs. 5a, &. 



Polystomella Sagra d'Oebigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 

 1839, Foraminiferes, p. 55, pi. 6, figs. 19, 20. 



Description. — Test bilaterally symmetrical, subcircular in side 

 riew; peripheral margin rounded, ten or more chambers in the last 

 formed coil; sutures distinct, curved, slightly depressed in the last 

 formed portion, not at all depressed in the early part of the coil; 

 early half of the coil with definite raised, longitudinal ribs, corre- 

 sponding to the bridging over the sutures, persisting longest on the 

 peripheral portion of the test, later portion smooth; bridging of 

 earliest portion of coil regular, short, in the last formed sutures in- 

 creasing considerably in length; apertural face smooth, punctate; 

 roughly triangular in outline, the angles rounded; aperture a very 

 narrow slit at the base of the apertural face of the chamber. 



Diameter 0.65 mm. Cat. No. 324688, U.S.N.M. 



The only station at which this species was obtained is a Pleistocene 

 deposit at U.S.G.S. No. 5850, loose shells and marl from near Mount 

 Hope, one-fourth mile from present beach and 6 to 8 feet above high 

 tide. 



A comparison of this figure with the original given by d'Orbigny 

 in his tuua .monograph will show the very striking similarity be- 

 tween the Cuba and Panama specimens, and I have no hesitation in 

 referring this material to d'Orbigny's species. 

 8370°— 18— Bull. 103 6 



