78 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



coil, wall smooth except near the aperture on the ventral side where 

 there is usually a papillose area of greater or less extent ; periphery 

 usually somewhat rounded; sutures on the dorsal side with a single 

 simple angle ; below usually divided into two deep lobes by deep con- 

 strictions. 



Diameter, 1-2.5 mm. Cat. Nos. 324699-08, U.S.N.M. 



This species is common in the lower horizons of the area occurring 

 at the following stations : Culebra formation, 6009, 6012a, d, 6019c, d, 

 6027 ; Emperador limestone, 6015, 6016 ; Gatun formation, 6029a, b, c. 



At some of these stations specimens are rather frequent. In the 

 matrix this species may often be indistinguishable in a superficial ex- 

 amination from worn centers of Orbitoids or Numniulites. It is a 

 common Tertiary species. 



Family MILIOLIDAE. 



Genus QXJINQUELOCULINA d'Orbigny, 1826. 



QUINQUELQCULINA SEMINULUM (Linnaeus). 



Plate 27, figs. 4a, b; plate 28 ; plate 29, figs, la-e, 



Serpula seminulum Linnaeus, Syst. Nat., eel. 10, 1758, p. 7S6 ; ed. 13 



(Gmelin), 1758, pp. 37, 39. 

 Quinqueloculina seminulum d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 303, 



No. 44. 

 Miliolina seminulum Williamson, Rec. Foram. Great Britain, 1858, p. 85, 



pi. 7, figs. 183-189.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 



1884, p. 157, pi. 5, figs. 6a, 6, c. 



Description. — Test oval in front view; thickest in the middle, 

 visible exterior composed of five chambers, three visible from one 

 side and four from the other, sutures slightly depressed, distinct: 

 wall smooth, periphery rounded, aperture somewhat contracted, 

 usually with a single simple tooth. 



Length about 1 mm. Cat. Nos. 324709-13, U.S.N.M. 



Very typical specimens were obtained from U.S.G.S. No. 5850, 

 among loose shells and marl from near Mount Hope, from ditch 

 through swampy ground, one-fourth mile from present sea beach and 

 6 to 8 feet above high tide (Pleistocene). Specimens very similar 

 but slightly more rotund were obtained from the Gatun formation, 

 No. 6036, in dark colored, fine grained, sandy clay marl, at Monkey 

 Hill, Mount Hope Station. 



Varietal forms here figured and which may be referred to Q. semi- 

 nulum were obtained from the Culebra formation at No. 6010, from 

 dark clay, north of Pedro Miguel Locks; 6019a, a single specimen 

 from lower limestone of Las Cascadas section; 6025, a single glau- 

 conitic specimen from foraminiferal marl about 200 yards south of 



