324 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



the accompanying figures with those given by Gravell and Hanna 

 sliows only slight divergences, and this is supported by comparison 

 of Mexican specimens with material identified as G. moodyhranchsmi^ 

 from a well core in Montgomery County, Tex. 



PUsioty'pes.—V.S.'^:^l. nos. 497885, 497887, and 497888. 



Other specimens.— U.S.IUM. no. 497886. 



Occurrence.— Tantojucsi formation, Jackson Eocene, in Tantoyuca 



area. 



CAMERINA JACKSONENSIS Gravell and Hanna 



Plate 13, Figube 6 ; Plate 20, Figure 8 ; Plate 22, Figure 9 



1935. Camerina jacksonemis Geavell and Hanna, Journ. Pal., vol. 9, p. 331; 

 pi. 29, figs. 1-5, 7-8, 10-11, 13-14. 



Mexican specimens identified as C. jachsonemis may be described 



as follows: 



Test small, lenticular, completely involute. The septa are of clear 

 shell material, radiating, straight to slightly curved, and generally 

 obscurely beaded toward the mnbonal region, where there is a mass 

 of clear shell material of varying extent. Diameter (average for 

 10 specimens), 1.6 mm; thickness, average 0.6 mm. 



Sections show a regularly coiled test of 4 to 4>/2 whorls with 

 15 to 19 chambers in the final whorl. The septa are oblique and 

 show a gentle, even curvature. The spacing of the septa appears 

 to be somewhat variable, some specimens showing open spacing with 

 chambers nearly as wide as long (see pi. 20, fig. 8) and others a much 

 closer spacing with chambers correspondingly more elongate. Typi- 

 cal specmiens, as figured by Gravell and Hanna, show stronger bead- 

 ing than is usually shown by the Mexican material, but this is con- 

 sidered to be insignificant. 



PZesw)%/>es.— U.S.N.M. nos. 497889 and 497890. 



Occwrrence. — Occurs fairly abundantly in the lower part of the 

 Tantoyuca formation, Jackson Eocene. 



CAMERINA JACKSONENSIS GLOBOSA new variety 



Plate 13, Figubes 1, 2 ; Plate 20, Figubes 4, 5 ; Plate 22, Figures 5, 6 



Test small, stoutly lenticular to subglobose, completely involute, 

 with sharply keeled periphery. The sutures are seen to be radiate 

 and may be raised into ribs, which tend to be beaded to a variable 

 extent, especially toward the center, where they frequently coalesce 

 into a boss of clear shell material. Diameter, up to 2.0 mm (average 

 1.7 mm) ; thickness, average 0.9 mm. 



Sections show the test to be rather tightly coiled, consisting of 

 41^ to 5 whorls, with 15 to 17 chambers in the final whorl. The 

 septa are oblique and gently curved throughout their length. 



