SPECIES OF CAMERINIDAE BARKER 319 



incomplete or immature specimens, adult tests showing generally 

 24 to 28 chambers in the last whorl. The chambers are long and 

 narrow, the length being about five times the width, the septa thin 

 and regularly curved throughout. 



Cole's O. cushmani is considered to be the same as Cushman's 

 O. oliveri after careful comparison of topotype material of both 

 species (from the Guayabal of the Guayabal type locality and the 

 Moctezuma River, respectively), although it is possible that Cole also 

 included in his species forms referred by the writer to OifercuUnoides 

 vaughani (Cushman), q. v. 



0. oUveri is considered to be intermediate between O. coohei (Cush- 

 man) and 0. vaughani (Cushman) and may perhaps be ancestral 

 to both. These species have all been referred to Operculinoides by 

 Hanzawa, and the involute nature of O. oliveri and O. vaughani is 

 clearly seen on plate 11, figures 1-3, of the present account. 



Plesiotypes.—U.S.'^M. nos. 497864 and 497865. 



Occun-ence. — So far as is known, restricted to the Guayabal 

 (Tempoal of ver Wiebe and Muir, Claiborne). 



OPERCULINOIDES VAUGHANI (Cushman) 



Plate 11, Figukes 2, 3 



1921. Operculina vaughani Cushman, U. S. Geol. Surv. Prof. Paper 128-E, p. 



128, pi. 19, figs. 6-7. 

 1933. Openulina oUveri Ellisor, non Cole, Bull. Amer. Assoc. Petr. Geol., vol. 



17, p. 1299, pi. 2, fig. 15. 



1935. Operciiliiia vaughani Cushman, Gravell and Hanna, Journ. Pal., vol. 9, 



p. 334, pi. 29, figs. 6, 9, 12, 16-21. 



As this species has been well described recently by Gravell and 

 Hanna, and specimens so identified in the Mexican material are rare, 

 it is not considered necessary to give here a detailed description. 

 The species differs from O. oliveri (Cushman) in being of smaller 

 size, rather more tightly coiled, and narrower and more numerous 

 chambers and in having more regularly beaded sutures. In Mexico 

 it occurs rather high in the Claiborne and is much less frequent than 

 O. oUveri. The best specimens have been found in the Guayabal 

 (Tempoal), Claiborne Eocene, of the Guayabal type locality of Cole; 

 it also has been observed in the Guayabal exposed in the neighbor- 

 hood of Tantoyuca, Veracruz. 



OPERCULINOIDES TUBERCULATUS (Vaughan and Cole) 



Plate 14, Figures 3, 5 ; Plate 20, Figures 9, 11 



1936. Operculina tuherculata Vaughan and Cole, Proc. U. S. Nat. Mus., vol. 83, 



p. 488, pi. 35, figs. 1-4. 



