116 BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



Test plano-convex, usually attached to various objects by the 

 flattened dorsal side, trochoid; wall calcareous, coarsely perforate;; 

 aperture peripheral, at the base of the chamber, sometimes extending- 

 ventrally, but typically with a long slit-like extension between the 

 inner margin of the chamber on the dorsal side and the previous 

 whorl nearly or fully the length of the chamber. 



Cretaceous to Recent. 



The genus Cibicides and its related Planulina present one of the 

 most baffling problems in the Foraminifera. Many of the forms are 

 attached which give varied form to the general shape of the test. In 

 addition there is a very great difference between the megalospheric 

 and microspheric forms. The latter becomes progressively more 

 spread out and campanulate, the chambers becoming long and narrow 

 but the ventral side usually with the chambers extending into the 

 umbo. In many of the forms there is a great variation in the surface 

 characters due to thickening of the test and consequently a greater 

 amount of surface irregularity and ornamentation. 



The whole group should be studied with Planulina with large series^ 

 and sections made to determine the relationships of the size of the 

 proloculum to the various forms. 



The literature is also very involved, as names have been used in a 

 particularlj^ loose sense without reference to the original types which 

 are in many cases only different from the forms later assigned to them. 

 In the following pages are given a few of the species of the Atlantie 

 which seem fairly well characterized: 



CIBICIDES REFULGENS Montfort 



Plate 21, figures 2 a-c 



"Hammonia Balanus seu Balanoidea," Soldani, Testaceographia, vol. 1^. 

 pt. 1, 1789, p. 58, pi. 46, figs, nn, oo. 



Cibicides refulgens Montfort, Conch. Syst., vol. 1, 1808, p. 122. — Cushman, 

 Special Piibl. No. 1, Cushman Lab. Foram. Res., 1928, pi. 50, figs. 2 a-c. 



Truncatulina refulgens d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 279, pi. 13, 

 figs. 8-11; Modeles, No. 77. — Carpenter, Parker, and Jones, Introd. 

 Foram., 1862, p. 201, fig. 32, E. — Parker, Jones, and H. B. Brady, Ann. 

 Mag. Nat. Hist., ser. 3, vol. 16, 1865, p. 31, pi. 2, fig. 76.— H. B. Brady, 

 Nat. Hist. Trans. Northumberland and Durham, vol. 1, 1865-1867 (1867), 

 p. 105, pi. 12, fig. 9 a-c. — Parker, Jones, and H. B. Brady, Ann. Mag.^ 

 Nat. Hist., ser. 4, vol. 8, 1871, p. 176, pi. 12, fig. 139.— Terrigi, Atti 

 Accad. Pont. Nuovi Lincei, vol. 35, 1883, p. 197, pi. 3, fig. 40.— H. B. 

 Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 659, pi. 92, figs. 

 7-9. — Sherborn and Chapman, Journ. Roy. Micr. Soc, 1886, p. 756, 

 pi. 16, fig. 13 a-c. — Terrigi, Mem. Accad. Lincei, ser. 4, vol. 6, 1889, 

 p. 117, pi. 8, figs. 1-3. — Egger, Abhandl. kon. bay. Akad. Wiss. Miinchen, 

 CI. II, vol. 18, 1893, p. 401, pi. 16, figs. 31-33.— Goes, Kongl. Svensk.. 

 Vet. Akad. Handl., vol. 25, No. 9, 1894, p. 89, pi. 15, figs. 775, 776.— Jones, 

 Pal. Soc, 1895, p. 302, pi. 5, fig. 31. — Chapman, Journ. Roy. Micr. Soc.,, 

 1898, p. 1, pi. 1, fig. 1. — MiLLETT, Journ. Roy. Micr. Soc, 1904, p. 491.— - 



