2 PROCEEDINGS OF THE NATIOISTAL MUSEUM vol.72 



The globular forms referred to Siphoninoides need additional 

 study to reveal their full characters. Specimens are rare, hoAvever, 

 and sections have not been fully studied as they deserve to be. 



That there are many distinct species will be seen by a study of the 

 accompanying plates. The species have definite stratigraphic and 

 geographic distributions as will be indicated. 



Genus SIPHONINA Reuss, 1850 



Siphonina Reuss (Type S. fimhriata Reuss), Denkschr. Akad. Wiss. Wieu, vol. 

 1, 1850, p. 372.— Terquem, M6m. Soc. Geol. Fi-ance, ser. 3, vol. 2, 1882, p. 84.— 

 CusHMAN, Smithsonian Misc. Coll., vol. 77, No. 4, 1925, p. 45; Contrib. Cush- 

 man Lab. Foram. Res., vol. 3, pt. 1, 1927, p. 77. 



Truncatulina (part) of various authors. 



Test free, trochoid, composed of numerous chambers arranged in 

 a somewhat irregular spiral, usually biconvex; wall calcareous, per- 

 forate, the periphery often carinate and the carina jfimbriate in some 

 species; aperture in the adult just below the periphery on the ventral 

 side, elliptical with usually a short neck and often a phialine lip. 



SPECIES FROM THE UPPER CRETACEOUS 

 SIPHONINA PRIMA Plummer 



\ Plate 2, figs. 4 a-c 



Siphonina prima Plummek, Univ. Texas Bull. 2644, 1927, p. 148, pi. 12, figs, 

 4 a-o. 



Test small, nearly circular, about equally biconvex but much com- 

 pressed, periphery angled, sharply acute and delicately serrate, very 

 slightly lobate; chambers usually five in the last-formed volution, 

 very slightly inflated on the ventral side; sutures distinct, obliquely 

 curved, marked by the serrate edges of the chambers of the dorsal 

 side, not depressed; on the ventral side, more nearly radial, very 

 slightly curved, somewhat depressed; wall smooth, distinctly and 

 somewhat coarsely perforate, aperture a small, narrowly elliptical 

 opening on the ventral side close to the periphery, the elongate axis 

 in the axis of coiling without a definite neck. 



Diameter up to 0.25 mm. ; thickness 0.12 mm. 



The types of this species are from the Midway Eocene of Texas 

 where it is fairly common. To Mrs. Plummer I am indebted for 

 the opportunity of studying material from the type locality. Mrs. 

 Plummer has also recorded the species from the Upper Cretaceous, 

 Ripley formation of Owl Creek, Mississippi, as well as at one local- 

 ity in the topmost ISTavarro clays of Texas. Like many other genera 

 which originated in the uppermost Cretaceous, the main develop- 

 ment is in the Eocene. Mrs. Plummer also records its occurrence in 



