REPOET OK THE FORAMINIFERA. 
527 
The test of Marginulina is curved or nearly straight, sometimes slightly helicoid at 
the commencement ; the linear portion is round or nearly so in transverse section, and 
the later segments are generally subglobular. The aperture is marginal and either simple 
or slightly radiate. Morphologically the genus stands midway between the Dentaline 
varieties of Nodosaria and the longer forms of Cristellaria ; whilst it differs from 
Vaginulina chiefly by the absence of any marked lateral compression. At best the 
position is very ill defined, and the vague sense in which the generic term has not 
un frequently been employed has been a source of much confusion of nomenclature. 
The genus Marginulina is very widely diffused, being found in one form or other in 
all the great oceans and at almost every depth ; but as compared with the allied genera, 
it is nowhere abundant. As a fossfl it makes its earliest appearance in the Lower Lias, 
and it occurs in microzoic rocks of almost every subsecpient geological age. 
Marginulina glabra, cl’Orbigny (PL LXY. figs. 5, 6). 
Marginulina glabra, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 259, No. 6; — Modele, No. 55. 
„ elongata , Id. 1840, Mdm. Soc. g6ol. France, vol. iv. p. 17, pi. i. fig. 22. 
„ pedum, Id. 1846, For. Foss. "Vien., p. 68, pi. iii. figs. 13, 14. 
„ similis, Id. Ibid. p. 69, pi. iii. figs. 15, 16. 
„ pediformis, Bornemann, 1855, Zeitscbr. d. deutscb. geol. Gesellscli., vol. vii. p. 326, 
pi. xiii. fig. 13. 
„ eontrada, Costa, 1856, Atti dell’ Accad. Pont., vol. vii. p. 186, pi. xiii. fig. 10. 
„ abbreviata, Karrer, 1861, Sitzungsb. d. k. Ak. Wiss. Wien, vol. xliv. p. 445, 
pi. i. fig. 7. 
„ incequalis, Reuss, 1862, Ibid. vol. xlvi. p. 59, pi. v. fig. 13. 
„ infarda. Id. 1863, Ibid. vol. xlviii. p. 48, pi. iii. figs. 36, 37. 
„ opaca, Stache, 1864, Novara-Exped., geol. Tbeil, vol. i. pt. 2, p. 214, pi. xxii. 
fig. 47. 
„ angistoma, Id. Ibid. p. 213, pi. xxii. fig. 46. 
„ mucronulata, Id. Ibid. p. 215, pi. xxii. fig. 48. 
,, glabra, Parker, Jones, and Brady, 1865, Ann. and Mag. Nat. Hist., ser. 3, vol. xvi. 
p. 27, pi. i. fig. 36. 
„ „ Brady, 1867, Proc. Somerset. Arcli. and Nat. Hist. Soc., vol. xiii. p. 109, 
pi. ii. fig. 22. 
, subbullata, Hantken, 1875, Mittbeil. Jahrb. d. k. ungar. geol. Anstalt, vol. iv. 
p. 46, pi. iv. figs. 9, 10. 
,, splendens, Id. Ibid. p. 87, pi. iv. fig. 11. 
„ pediformis, Id. Ibid. p. 45, pi. iv. figs. 12, 13; pi. v. 
%• 8 - 
Cristellaria articulata, Seguenza, 1880, Atti. R. Accad. dei Lincei, ser. 3, vol vi. p. 140, 
pi. xiii. figs. 10, 10a. 
„ trunculata, Berthelin, 1880, Mem. Soc. g6ol. France, ser. 3, vol. i., Mem. v. p. 53, 
pi. iii. figs. 26, 27. 
D’Orbigny’s Model, No. 55, forms an excellent central type of this species. It 
represents a short, somewhat tapering, Nodosariform shell, curved near the initial end 
