130 CARBONIFEROUS AND PERMIAN FORAMINIFERA. 



Prof. Rupert Jones's entire approval. Between the published figures of the specimens 

 from Permian and Cretaceous beds respectively no difference in characters can be detected 

 that would justify the most trivial distinction, and it is surely too late in the day to 

 accept geological age alone, as sufficient basis for zoological species. 



The figure (PI. X, fig. 19) has been copied from the original engraving in Professor 

 W. King's Monograph, no specimens with quite the same characters having been 

 found in the Permian beds since Professor Jones's early researches. 



Distribution. The only recorded occurrence of Carboniferous or Permian specimens 

 of Dentalina multicostata is in the Upper Magnesian Limestone of Byers Quarry, 

 Durham. 



Family, GLOBIGERINIDA, Carpenter. 



Genus. TEXTULARIA, Defrance. 



POLYMORPHUM, Soldani. 



NAUTILUS, Soldani, Batsch. 



TEXTULARIA, Defrance, d'Orbigny, Bronn, von Miinster, Romer, Reuss, Parker and Jones, 



Williamson, Carpenter, Dawson, Brady, fyc. 



TEXTILARIA, Ehrenberg, Reuss, Schultze, Karrer, Giimbel, Stache, Schwager, Terquem, ij-c. 

 CLIDOSTOMUM (?), GRAMMOSTOMUM, HETEROSTOMUM, HETEROSTOMELLA, PROROPORUS, GUTTU- 



LINA, POLYMORPHINA, RHYNCHOPLEURA (?), RnYNCHOPLECTA (?), &c. (in part), Ehrenberg. 



General Characters. Shell free, regular, equilateral; conical, pyriform, oblong, or 

 cuneiform. Segments numerous, arranged in two alternate parallel series ; septal orifice 

 at the centre of the umbilical margin of each segment, close to its line of contact with the 

 preceding opposite segment. Aperture simple or labyrinthic. 



What is to be said of the Palaeozoic Textularice will perhaps be best detailed in the 

 account of the individual species. There is nothing to distinguish the Carboniferous 

 representatives of the genus, as a group, from those of any subsequent age. They 

 generally pertain to the rough thick-shelled forms and, as might be expected, have a 

 tendency to labyrinthic internal structure. 



The Permian species are still very obscure and, comparatively speaking, specimens are 

 rare ; material is as yet too scanty for the foundation of any very positive conclusions as 

 to the limits of their varietal modifications. 



