﻿DENTALINA. 



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Dentalina multicostata, d'Orbigny. PI. X, fig. 19. 



Dentalina multicostata, oVOrbigny, 1840. Mem. Soc. Geol. Fr., vol. iv, p. 15, 



pi. i, figs. 14, 15. 



— Kingi, Jones, 1850. In King's Monog. Perm. Foss., p. 1 7, pi. vi, figs. 2, 3. 



— — Beuss, 1854. Jahresb. d. Wetterauer Gesellsch., vol. for 1851 — 



1853, p. 73. 



— — Geinitz, 1861. Dyas, Heft i, p. 122, pi. xx, fig. 33. 



Characters. — Shell elongate, arcuate, longitudinally costate ; costse numerous, 

 delicate. Chambers subglobose ; sutures straight, constricted. Length ^ to yg- inch 

 (1-0 to 2-5 mm.). 



D'Orbigny's figure of Dentalina multicostata is the first quite satisfactory represen- 

 tation of a finely costate, curved Nodosarian (as distinct from the thick-ribbed D. 

 obliqua, Linne), with the successive chambers rapidly increasing in size and not very 

 numerous. It is true that the Orthoceras corniculum of Soldani {Dentalina cornicula of 

 D'Orbigny 1 ) is in most respects a very similar shell and in point of order its name 

 would take precedence, but its excessively large, smooth, globose primordial chamber 

 gives the impression of individual monstrosity, and the figure would not therefore be 

 satisfactory as a standard of reference for the normal form. In our notes on the 

 Soldanian species of Poraminifera my colleagues and myself accept D. corniculum as a 

 sub-varietal form on the ground of its large non-costate primordial segment. There is 

 another striate curved Nodosarian in the ' Testaceographia ' named by D'Orbigny 

 Nodosaria nodosa? This is a finely costate Dentalina like D. multicostata, but much 

 more slender and elegant in outline, and with a larger number of segments all of 

 regular elliptical shape. It would not be difficult to select many other " species " from 

 the works of subsequent writers differing only in the most trifling particulars from 

 D. multicostata, but such a review at the present moment would not serve any good 

 purpose ; it is sufficient to say that in sacrificing the name given originally to the Permian 

 examples of this species, and associating them with D'Orbigny's Cretaceous form, I have 



1 Soldani, 'Testaceographia,' vol. i, part 2, p. 98, pi. cv, fig. k. d'Orbigny, 'Ann. Sci. Nat.,' vol. vii, 

 p. 255, No. 47. Parker, Jones, and Brady, 'Ann. and Mag. Nat. Hist.,' ser. iv, vol. viii, p. 161, pi. ix, 

 fig. 56. Prof. Rupert Jones calls my attention to the fact that we have unwittingly, in the paper last 

 quoted, repeated an error made by d'Orbigny in respect to the name of this variety. Soldani's term is 

 Orthoceras " corniculum " (a little horn) ; d'Orbigny makes it Dentalina" carmcnta'' (a little crow). There 

 can be no doubt what was intended, and the termination originally given by Soldani must be adhered to. 



2 Vide 'Ann. and Mag. Nat. Hist.,' ser. iv, vol. viii, p. 158, pi. ix, fig. 55. 



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