182 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



I have doubtfully referred this form. The rather large and open umbilicus is not 

 cmite in accordance with the more typical forms of G. diadema, though it has been 

 pointed out that that species has sometimes a small, sometimes a comparatively 

 large umbilicus. 1 



It must be observed that if the interpretation of this fossil is the correct one, 

 the horizon of the species would be extended below that in which it has hitherto 

 been identified, viz. the Yoredale Series. 



Some specimens (casts) from Redesdale, Yorkshire, kindly lent to me by 

 Dr. Wheelton Hind (agreeing remarkably well with de Verneuil's excellent 

 figures 2 ), have been very useful to me for comparison with the Irish specimens. 

 The evidence in favour of the affinities of the latter here suggested seems fairly 

 well grounded, though the absence of the test in the pyritised casts, and of the 

 suture-line in the other two specimens, introduce an element of doubt. 



There is little likelihood that all the forms assigned to Glyphioceras diadema 

 really belong to the species described by Bey rich under that name, but as it has 

 attained the distinction of being a very variable species it is hard to determine 

 what are its limitations. 



Localities. — Kinsale, county of Cork. " Four miles east of Loughrea," county 

 of Gal way. 



Group or Glypiiiooeras (Beyeichoceeas) reticulatum. 

 Glyph lor ki; as (Beyeichoceeas) reticulatum, J. Phillips, sp. Plate XLIX, figs. 2 a, h, 



8 a, h. 



1836. Goniatites reticulatus, J". Phillips. Geology of Yorkshire, pt. 2, p. 235, 



pi. xix, figs. 26— 32. 

 Gibsoni, /. Phillips. Ibid., p. 230, pi. xx, figs. 13 — 18. 

 1841. jugosus, T. Brown. Trans. Manchester Geol. Soc, vol. i, 



p. 215, pi. vii, figs. 14, 15. 



1843. Gibsoni, jugosus, reticulatus, /. Morris. Cat. Brit. Foss., 



pp. 179, 180. 



1844. Gibsoni, reticulatus, F. M'Coy. Synops. Carb. Foss. Ireland, 



pp. 13, 15. 

 1848. reticulatus, J. H. Cumming. Isle of Man, p. 357. 



Gibsoni, jugosus, reticulatus, H. G. Bronn. Gesch. der 



Natur, vol. iii, pp. 542, 544. 



1850. Aganides diadema (pars), A. d'Orbignij. Prod, de Paleont. stratigr., vol. i, 



p. 11(5. 



1 ' Cat. Foss. Ceph. Brit. Mus.,' pt. 3, 1897, p. 204. 



2 ' Geologic de la Kussie d'Europe,' loc. cit. 



