l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



Test small, lenticular, thickest in center, gradually sloping to the 

 periphery, which is broadly rounded ; diameter about 2.0 mm ; thick- 

 ness about 0.8 mm. Test composed of four to five whorls. 



These specimens are less compressed and have thicker chamber 

 roofs than those of Camerina sp. a and C. panamensis (Cushman) 

 (12, p. 98, pi. 43, figs. 9, 10). 



Genus OPERCULINA d'Orbigny 

 OPERCULINA sp. cf . 0. COOKEI Cushman 



Plate I, figs. 7-9 

 Opcrciilina cookei Cushman (16, pp. 127, 128, pi. 18, figs, i, 2). 



These specimens differ somewhat from the typical Operciilina 

 cookei. 



Test small, with a large excentrically placed thick swelling occupy- 

 ing about one half the test, surrounded by a thin flange. The diam- 

 eter of the test measured from the periphery of the apertural face 

 across the center is about 2.75 mm ; thickness through center about 

 0.8 mm ; outside the central area about 0.2 mm. Test composed of 

 three and one half whorls, which widen rapidly ; septa gently curved 

 to near the periphery, where they turn backward abruptly. Chambers 

 numerous, 30 to 34 in last whorl. 



The center of the thickened part of the test is composed of an 

 umbo of light-colored shell material and is about 0.5 mm in diameter. 

 The sutures are but slightly raised ; surface slightly depressed be- 

 tween the sutures. 



These specimens differ from O. cookei as described by Cushman 

 from the Ocala Limestone (upper Eocene), United States Geological 

 Survey Station 71 16, near Oakfield, Ga., in that they are only about 

 half as large, and the width of the whorls does not increase quite so 

 rapidly as does that of the whorls of typical 0. cookei. 



Localities and geologic horizon. — Fairly abundant at locality 163. 

 Thin sections of material from localities 148, 1149, and 1162 contain 

 a few poor sections of an Operculina which appear to be Operculina 

 sp. cf. O. cookei. 



That the above localities are upper Eocene is shown by the as- 

 sociation of Discocyclina (Asterocyclina) asterisca (Guppy), D. 

 (Asterocyclina) kugleri Gravell n. sp., L. (Lcpidocyclina) trinifatis 

 H. Douville, and L. (Lepidocyclina) macdonaldi Cushman. 



