180 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



1884. " Ammonites diadema, L. v. Bueh," E. Beyrich. Zeitschr. Deutsch. Geol 



Gesell., vol. xxxvi, pp. 

 213—215. 



1888. Goniatites diadema, B. Etheridge. Brit. Foss., vol. i, Palaeozoic, p. 311. 

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



1889. Gastrioceras diadema, E. Holzapfel. Palaont. Abhandl., Dames und 



Kay ser, vol. v, i, p. 26. 



1890. Glyphioceras diadema, G. Steinmann und L. Doderlein. Elemente der 



Paliiontologie, pt. 2, p. 393. 



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



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

 of an Acquired Characteristic." 



1895. K. A. v. Zittel. Grundziige der Paliiontologie, 



p. 399. 

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



British Museum, pt, 3, p. 202, 

 figs. 98 a—c. 

 — — James Perrin Smith. " Development of Glyphio- 



ceras and the Phylogeny of the Glyphio- 

 ceratidse," Proceed. California Acad. Sci., 

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

 1899. Goniatites striolatus, James Spencer. Proceed. Yorkshire Geol. and 



Polytech. Soc, new ser., vol. 

 xiii, pt. 4, p. 391. 

 1901. Glyphioceras diadema, Wheelton Hind and J. A. Howe. Quart. Journ. 



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

 1903. Wheelton Hind. Brit. Assoc. Adv. Sci., Belfast, 



1902, p. 215, "Life-zones in 

 the Carboniferous Bocks." 



Description. — " Shell variable, discoidal, umbilicated, the young much more 

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

 two-fifths of the diameter of the shell ; height of outer 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. Whorl 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 

 by 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. Chambers very shallow, eighteen or nineteen to a whorl. Test 

 ornamented with fine strias, 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 periphery; in very young shells the strias are 



