NEW TERTIARY FORAMINIFERA VAUGHAN AND COLE 491 



Plate 36, figure 4a, illustrates a decalcified Canada balsam impreg- 

 nation of the canals in the marginal cord and an interseptal canal, 

 magnified 210 times. 



Cohjpes.—U.S.lsM. no. 495190. 



Localities. — Cotypes, road below National Cemetery, Vicksburg, 

 Miss.; Robinson Quarry, sec. 19, T. 5 K, R. 9 E., 3 miles east of 

 Brandon, Miss.; and one-fourth mile west of Floral Church, creek 

 beneath bridge, 81/2 sec. 27, T. 3 N., R. 14 E., Covington County, Ala. 

 All collected by Dr. C. Wythe Cooke. 



Geologic horizon. — Bj^ram calcareous marl, topmost formation of 

 the Oligocene Vicksburg group at and near Vicksburg, Miss. 



OPERCULINOIDES SEMP.IESI, new species 



Plate 37, Figttres 10-13, probably Figure 14 ; Plate 3S, Figures 1, 2, probably 



Figures 5, 6 



Test small, completely involute, lenticular, with a slightly extended 

 thinner edge in fully adult perfect specimens. Diameter, 1.75-2.8 

 mm; thickness, 0.55-0.65 mm. In many specimens there is a small 

 central knob. 



The sutures on perfect specimens are somewhat raised and are 

 curved as shown by the upper left specimen in plate 37, figure 10. 

 The number of chambers in the specimen shown on plate 37, figure 

 11, is 18, and there are about 3% coils; the number in the specimen 

 shown on plate 38, figure 2, is 19. Other specimens that appear to 

 belong to the same species have fewer chambers, as few as 14 (pi. 

 37, fig. 14) or 15 (pi, 38, fig. 5). The proximal part of the chamber' 

 wails is nearly straight, while the distal part curves backward. 



Cotypes.— \].S.'^.iL no. 495191. 



Localities. — The cotypes are from the arroyo in the center of 

 Meson Village, Canton of Tuxpan, State of Veracruz, Mexico. 

 Slightly worn but typical specimens were collected by T. Wayland 

 Vaughan (M 36 V) at Azteca Incline, Zacamixtle, Canton of Tux- 

 pan, Veracruz. Other localities are on the east side of Rio Buena 

 Vista, opposite La Ceiba crossing, along the slope, about 60 feet above 

 the base of the bluff on the river (M 55 V and M 56 V). Specimens 

 that appear to belong to this species were found at many localities 

 where the Meson formation is exposed, but to be sure of the identi- 

 fication thin sections are necessary. All the collections were made by 

 geologists connected with the Aguila Co, 



Geologic horizon. — Oligocene Meson formation. 



Remarks. — O. seinmesi is a small, robustly lenticular species with 

 a peripheral flange in perfect adult specimens. Apparently the 

 chambers in the last coil range from 14 to 19, but larger suites of 



