186 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



Glyphioceeas (Beyeichoceras) bilingue, J. W. Salter, sp. Plate XLIX, fig. 1. 



1864. Goniatites bilinguis, J. W. Salter. Mem. Geol. Surv., Geology of the 



Country around Oldham, p. 60, 

 figs. 14 a — c. 



1885. R. Etherulge. Mem. G-eol. Suit., Geology of the 



Country around Rhyl, Abergele, 

 and Colwyn, p. 17. 



1888. Brit. Foss., vol. i, Paheozoic, p. 311. 



1896. H. Bolton. Trans. Manchester Micro. Soc. for 



1895, pp. 130, 134. 



1897. Gltphioceras bilingue, A. H. Foord and G. C. Crick. Cat, Foss. Ceph. 



British Museum, pt. 3, p. 192, 

 fig. 93 (suture-line). 



1901. Wheelton Hind and J. A. Howe. Quart. Journ. 



Geol. Soc, vol. lvii, p. 356, etc. 



1902. Wheelton Hind. Brit. Assoc. Adv. Sci., Glasgow, 



1901, p. 296, "Life-zones in 

 the British Carboniferous 

 Rocks." 



1903. Ibid., Belfast, 1902, p. 218, etc., 



" Life-zones in the British 

 Carboniferous Rocks." 



Description. — The following is the description of this species contained in the 

 ' Catalogue of Fossil Cephalopoda, British Mnsenm,' pt. 3, 1897, and is here 

 transcribed because it is based upon much more complete material than I have at 

 my disposal for describing the species : — " Shell compressed, involute ; greatest 

 thickness at the edge of the umbilicus rather more than four-ninths of the 

 diameter of the shell ; height of outer whorl nearly one-half of the diameter of 

 the shell. Whorls (? number) ; inclusion almost complete ; umbilicus infundibuli- 

 form, with angular margin and sloping sides, nearly one-fourth of the diameter of 

 the shell in width. Whorl bluntly sagittate in section, a little higher than wide ; 

 indented to about two-fifths of its height by the preceding whorl; periphery 

 convex, a little flattened ; sides feebly convex, with a double spiral furrow near the 

 periphery, their portion internal to the furrow flattened; inner area distinctly 

 marked off, narrow, sloping towards the umbilicus. Body-chamber occupying a 

 complete whorl ; aperture with a projecting tongue-like lobe on either side near 

 the periphery, and a deep broad hyponomic sinus. Chambers rather shallow. . . . 

 Test thin, its surface delicately reticulate ; transverse strias very finely crenulate, 

 strongly arched forward at the double concentric groove and forming a deep broad 

 sinus on the periphery; longitudinal strife very feeble." 



" All the examples of this species in the Jermyn Street Museum are either very 



