MILIOLIDA. 



1. BiLOCULiNA RiNGENS, Lamarck. Plate III, figs. 26 — 28. 



MiLiOLiTES KINGEN3, Lamarclc, 1804. Ann. Miis., vol. v, p. 351 ; vol. is, pi. 17, fig. 1. 

 Pyrgo l^vis, Befrance, 1824. Diet. Sc. Nat., vol. xx.xii, p. 273 ; Atlas, pi. 88, fig. 2. 

 BiLocULiNA BOLLOiDEs, D'Oa^., 1826. Aun. Sc. Nat., vol. vii,p. 297, No. l,pl. 16, figs. 1-4; 

 Modele No. 90. 



— RINGENS, 7^i., 1826. Ann. Sc. Nat, vol. vii, p. 297, No. 2. 



— Canariensis, Id., 1839. Foram. Canaries, p. 139, pi. 3, figs. 10-12. 



— IsABELLEANA, Id., 1839. For. Am^r. Mer., p. 66, pi. 8, figs. 17-19. 



; — Peruviana, Id., 1839. Foram. Ame'r. M^rid., p. 68, pi. 9, figs. 1-3 (and 



sub- varieties in pi. 8). 



— suBSPHJ3iacA,/rf., 1839. Foram. Cuba, p. 162, pi. 8, figs. 25-27. 



— BULLATA, S. Wood, 1843. Morris's Cat. Brit. Foss., p. 61. 



— CLYPEATA, B'Orb., 1846. For. Fos. Vien., p. 263, pi. 15, figs. 19-21. 



— SIMPLEX, Id., 1846. Ibid., p. 264, pi. 15, figs. 2.5-27. 

 Triloculina bipartita (a badly grown Biloculina), D' Orb., 1846. For. Fos. Vien., p. 275, 



pi. 17, figs. 1-3. 

 BiLOCULiNA RINGENS, Sow., 1850. Dixon's Foss. Sussex, p. 162, pi. 9, fig. 9, a. 



— TURGIDA, iJe?(«s, 1851. Zeitsch. Deutsch. Geol. Ges., vol.iii, p. 85,pl. 7, fig. 55. 



— RINGENS, Parker and Jones, 1857- Ann. Nat. Hist., ser. 2, vol. xix, p. 298, 



pi. 10, figs. 28-33. 

 _ — JVilliamson, 1858. Rec. Foram. Gt. Brit., p. 79, pi. 6, figs. 169, 170 ; 



pi. 7, fig. 171. 



— OBESA, Reuss, 1865. Sitzungsb. Akad. Wien., vol. 1, p. 450, pi. 5, fig. 7. 



Characters. — Shell, oval or sub-spherical, ultimate chamber projecting beyond the 

 penultimate all round, and having its margin more or less rounded. Aperture, at the 

 end of the last segment ; its shape and size variable, sometimes little more than a curved 

 slit. Length ^th to ,^th inch. 



We may take this as a sub-type, comprising the numberless varieties of Miliola which 

 show only two chambers externally, the ultimate and the penultimate. The form of the 

 margin, the extent to which the edges of the chambers overlap, the greater or less globosity 

 of the segments, and the shape of the aperture, differ in almost every specimen ; and, 

 although the general appearance of the shell is much affected by these variations, they are 

 of no value as characters on which to found any real specific subdivision. It is, 

 however, convenient to recognise some of the most important of the modifications of the 

 ordinary plan of growth, though the very fact of the inconstancy of their characters pre- 

 cludes our viewing them as anything more than varieties ; of these, perhaps, Biloculina 

 elon^afa, D'Orh.,^ B. depressa, D'Orb., B. sphcsra, D'Orb.,2 and B. contraria, D'Orb., are 

 the most important. 



1 Biloculina elongata, D'Orb., 1826. Ann. Sc. Nat., vol. vii, p. 298, No. 4 ; Parker and Jones, Phil. 

 Trans. 1865, p. 409, pi. 17, figs. 88, 90, 91. 



2 B. sphcera, D'Orb., 1839. Foram. Am. Mer., p. 66, pi. 8, figs. 13-6; Brady, 1864, Trans. Linn. 

 Soc, vol. xxiv, p. 466, pi. 48, fig. 1. 



