180 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



1884. " Ammonites diadema, L. t. Eiicli," E. Beyrich. Zeitscbr. Deutsch. Geol 



Gesell., vol. xxxvi, pp. 

 213—215. 



1888. GoNiATiTES DIADEMA, E. EtherUlge. Brit. Foss., vol. i, PalfBOZoie, p. 311. 

 ? — — STRIOLATTTS, B. Etheridge. Ibid., p. 313. 



1889. G-ASTEiocERAS DIADEMA, E. Iloh.apfel. Paliiont. Abliandl., Dames uiid 



Kayser, vol. v, i, p. 26. 



1890. Gltphiocera.s diadema, G. Steinmann vnd L. Doderlein. Elemente der 



Paliiontologie, pt. 2, p. 393. 



1894. — — A.Hyatt. Proceed. Amer. Philos. Soc, vol. xxxii, 



p. 620, pi. ii, fig. 27, " Phylogeny 

 of an Acquired CliaracterLstic." 



1895. — — K. A. V. Zittel. Grandziige der Paliiontologie, 



p. 399. 

 1897. — — A. H. Foord and G. C. Crick. Cat. Foss. Cepli. 



British Museum, pt. 3, p. 202, 

 figs. 98 a — c. 

 — — — James Pcrr in Smith. " Development of Glyphio- 



ceras and the Phylogeny of the Glyphio- 

 ceratidte," Proceed. Calif ornia Acad. Sci., 

 ser. 3, Geology, vol. i, pp. 110, 111. 

 1899. Goniatites steiolatus, Jame.<s Sj^encer. Proceed. Yorkshire Geol. and 



Polytech. Soc, new ser., vol. 

 xiii, pt. 4, p. 391. 

 1901. Gltphioceeas diadema, Wheclton Hind a^id J. A. Howe. Quart. Journ. 



Geol. Soc, vol. Ivii, p. 372, etc 

 1903. — — Wheeltoii Hind. Brit. Assoc Adv. Sci., Belfast, 



1902, p. 215, "Life-zones in 

 the Carboniferous Eocks." 



Dp-^rrijition. — " Shell variable, discoidal, iimhilicated, the j'oung much more 

 inflated than the adult ; greatest thickness near the edge of the umhilicus, about 

 two-fifths of the diameter of the shell ; height of oiiter whorl about one-half of the 

 diameter of the shell. Whorls (? number); inclusion nearly complete; umbilicus 

 shallow, about one-fifth of the diameter of the shell in width, the edge with a 

 slightly raised rim in the young shell, but wanting this in the adult. AVhorl almost 

 semilunate in section in the young, elongate-oval in the adult, higher than wide (in 

 the young the reverse of this is the case) ; indented to nearly one-half of its height 

 ])y the preceding whorl ; periphery narrowly convex ; sides inflated in the young, 

 compressed in the adult ; inner area flat, sloping towards the umbilicus, and thus 

 forming an obtuse angle with the sides of the shell. Body-chamber occupying at 

 least one whorl. Chamber.s very shallow, eighteen or nineteen to a whorl. Test 

 ornamented Avith fine strife, most of which bifurcate in the umbilical region in the 

 adult shell ; they are sigmoidal upon the sides of the shell, and form a backwardly 

 directed, linguiform sinus on the peri|)hery ; in very young shells the stria^ are 



