﻿GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 97 



HETEROSTEGINOIDES, new genus. 



Test generally lenticular, somewhat excentric, one side extended 

 peripherally more than the other, chambers rather coarsely per- 

 forate, embryonic chambers, often two, of nearly equal size, thick 

 walled, chambers added as in Heterostegina^ in a revolving series ex- 

 tending from the umbonal region on both sides to the periphery, 

 chambers hemispherical, the outer side strongly convex and all 

 coarsely perforate, the equatorial chambers larger than the lateral 

 ones and nearly spherical. 



Type of the genus. — Heterosteginoides panumensis, new species. 



HETEROSTEGINOIDES PANAMENSIS, new species. 



Plate 43, figs. 1-8. 



Test biconvex, somewhat more strongly convex on one side than on 

 the other, revolving edge indistinct, surface unevenly rugose, or ir- 

 regularly pustulate, thickest in the um.bonal region. Vertical section 

 showing the embrj^onic chambers as an equal pair of nearly spherical, 

 thick-walled chambers, equatorial chambers also nearly spherical, 

 lateral chambers hemispherical with the curved side outermost, ir- 

 regularly piled above the equatorial chambers. Horizontal section 

 showing the central chambers with the equatorial chambers arranged 

 in an irregular semi-spiral manner about them. 



Test small, between 1 and 2 millimeters in diameter. Cat. Nos. 

 324743-4, U.S.N.M. 



Occui^ence. — This species was abundant in the Culebra formation 

 at station 6025, from marl, south end of Bohio Ridge switch, relo- 

 cated line, Panama Railroad, collected by Vaughan and MacDonald. 

 There are also numerous specimens at station 6011, Culebra forma- 

 tion, along east side of Gaillard Cut, collected by Vaughan and Mac- 

 Donald. It was also collected in the Culebra formation at station 

 6024-(2, Rio Agua Salud, and is doubtfully present in the Emperador 

 limestone at stations 6015 and 6016, in Empire. 



This species, which in external appearance somewhat resembles a 

 small orbitoid or nummulite, may be distinguished from most species 

 of either group by its comparatively coarse pustulate exterior. In 

 section it can easily be recognized b}'^ its peculiar structure. 



Genus ORTHOPHRAGMINA. 



ORTHOPHRAGMINA MINIRLA., new species. 



Plate 41, fig. 1. 



Test circular, very small, slightl}^ more than 2 millimeters in 

 diameter, thickness somewhat less than half the diameter, central 

 portion very strongly umbonate, evenly rounded to a point about 



