TEXTULARIA. 131 



TEXTULARIA GIBBOSA, (FOrbiyny. 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 (?), Ekrenberg, 1854. Mikrogeologie, pi. xxxvii, No. 11, 



fig. 17. 



LAGEXOSA (?), Id. Ibid., fig. 15. 

 TEXTULARIA GIBBOSA, Parker, Jones, and Brady, 1865. Ann. and Mag. Nat. Hist., 



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



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

 119. 



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 Tcsstularia 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. 



