322 PROCEEDINGS OF THE NATIONAL MUSEUM vol.86 



pi. 12, fig. 3) ; these may appear only on weathering and are of value 

 in distinguishing this species from other closely similar small species. 

 Diameter, average 2.0 mm ; thickness, 0.5 mm. 



Sections show the test to be close-coiled, consisting of 4 to 5 whorls, 

 with 22 to 24 chambers in the final whorl. The septa are of mod- 

 erate thickness, oblique and gently curved, the chambers being only 

 slightly longer than wide. Owing to the rarity of the species in the 

 collections examined the material is considered insufficient for the 

 erection of a new species. 



Ooti/pes.—U.S.l^M. nos. 497874, 497875, 497876, and 497877. 



OccurreTwe.—Gnayahal (ver Wiebe's Tempoal), Claibor.ie Eocene; 

 rare. The description is based on specimens from the Tantoyuca 

 region, Veracruz ; collection of H. E. Rankin no. 277. 



? OPERCULINOIDES species 

 Plate 20, Figure 6; Plate 21, Figure 4 



Test small, compressed lenticular, sharply keeled, and completely 

 involute. The sutures are nearly straight, radiating, and show a 

 slight tendency to become beaded toward the center. The appearance 

 is similar to flattened specimens of Camerina jack.9on^nsis Gravell and 

 Hanna. Diameter (for 10 specimens), 1.3 mm; thickness, 0.3 to 

 0.4 mm. 



Sections show a test of 3 to 3i/^ whorls, with 11 to 13 chambers 

 in the final whorl. The septa are oblique and only slightly curved, 

 the chambers being slightly greater in width than in length. From 

 the scarcity and bad state of preservation of the material it is diffi- 

 cult to say whether the species should be referred to Camerhia or 

 Operculinoides, and for these reasons it is considered unwise to give 

 a name to the species until more and better preserved material is 

 available for further study. 



Cotypes.—U.S.l^iM. nos. 497878 and 497870. 



Occurrence. — ^^^ery rare in the Tantoyuca formation, Jackson 

 Eocene. The description is based on specimens from near Los Ajos, 

 Hacienda Santa Clara, southeast of Tantoyuca, Veracruz; collection 

 of Dr. H. Meyer no. 1471. 



Genus CAMERINA Bruguiere, 1792 



CAMERINA VANDERSTOKI (Rutten and Vermunt) 



Plate 13, Figure 7 ; Pl.\te 18, Figure 3 ; Plate 22, Figures 10-12 



1932. Nnmmulites vanderstoki Rutten and Vermunt, Proc. Sect. Sci. Kon. Akad. 

 Wetensch. Amsterdam, vol. 35, p. 240, pi. 1, fig. 8 ; pi. 2, figs. 6, 12. 



One of the commoner forms of Camerina found in Mexico has been 

 referred to C. vanderstoki, after careful comparison with the fig- 



