﻿TEXTULARIA. 



131 



Textularia gibbosa, d'Orbigng. PI. X, fig. 26. 



Textularia gibbosa, d'Orbigny, 1826. Ann. Sci. Nat., vol. vii, p. 262, No. 6, — 



Modele, No. 28 ; — Soldani, ' Testaceographia,' vol. i, part 2, 

 p. 119, pi. cxxxii, figs. I, K, &c. 



Textilaria recurvata (?), Ehrenberg, 1854. Mikrogeologie, pi. xxxvii, No. 11, 



fig. 17. 



— lagenosa (?), Id. Ibid., fig. 15. 



Textularia gibbosa, Parker, Jones, and Brady, 1865. Ann. and Mag. Nat. Hist. 5 



ser. iii, vol. xvi, p. 23, pi. ii, fig. 60. 



— — Id., 1871. Ibid., ser. iv, vol. viii, p. 168, pi. xi, figs. 115 — 



IIP. 



Characters. — Shell elongate, compressed, tapering, constricted at the sutures ; 

 depressed at the centre over the line of juxtaposition of the two series of segments ; 

 margin rounded. Chambers few in number, broad, ventricose, especially the final pair. 

 Texture coarse. Length ^ inch (1*25 mm.) or more. 



The name Textularia gibbosa may be accepted with advantage for the bold coarse- 

 shelled, somewhat compressed varieties of the genus, having inflated chambers and often 

 more or less irregular growth. They constitute a natural group between the more 

 delicate and regular Textularia globulosa of Ehrenberg, with its nearly spherical segments ; 

 and the compact T. sagittula of Defrance with its thin even margin. Such forms are 

 common amongst Tertiary fossils, sometimes attaining considerable size, and large indivi- 

 duals occasionally have their chambers subdivided by secondary septa. The dimensions 

 above appended to the description of Textularia gibbosa are those of the Carboniferous 

 specimens ; in Tertiary deposits they often attain a much larger size. 



Two of the figures of Carboniferous Textularia given by Dr. Ehrenberg in the 

 ' Mikrogeologie,' with the names T. lagenosa and T recurvata respectively appear to 

 possess the general characters of T. gibbosa though it is difficult to speak with anything 

 like certainty from drawings based on mere transparent rock-sections. 



Distribution. — In England Textularia gibbosa is found in both the Scar and the 

 Yoredale Limestones ; in Scotland in beds of the Lower Carboniferous Limestone Group 

 only; it also occurs in the Calcaire de Vise of Belgium and in some of the Carboniferous 

 deposits of Russia. 



