GLYPIIIOCERAS (SPHENOCEBA.S) CRENISTRIA. 157 



The shell attains a diameter of 60 mm. with a thickness of 4G mm. 



Affinities. — This species is distinguished from Glyphioceras striatum, J. Sow., by 

 its more globose form, and by its suture-line. 



Remarks. — This is a common and widely distributed species, as the long list of 

 references to it at the head of the description testifies. It has been found in the 

 British Isles, Belgium, and the Hartz. It is easily recognised by its globular 

 shape, and the suture-line is also characteristic. Casts of it are more frequently 

 met with than specimens having the shell preserved (probably owing to the tenuity 

 of the test) ; hence the suture-line is generally exposed. 



This species, like G. striatum (p. 100), appears to be rare in Ireland, and I can 

 only record two localities for it. The specimen from which M'Coy drew up the 

 description in liis ' Synopsis ' (loc. cit.) belonged apparently to a private collec- 

 tion, as it is contained in a list of species to which the following heading is 

 appended : — " The following fossils are described in my Synopsis, though not con- 

 tained in the cabinets " [i. e. those belonging to Sir R. Griffith's Collection]. The 

 Groniatites enumerated in this list are G. Broiviri, G. crenistria, G. sphsericus, 

 G. spiralis, and G. vittiger. No localities are attached to them. 



The largest individuals belonging to the present species have been found in 

 Belgium ; de Koninck records one having a diameter of 70 mm. and a thickness of 

 55 mm. as the largest lie had met with. M'Coy's specimen (' Synopsis,' loc. cit.) 

 measured 46'5 mm. in diameter and 38 mm. in thickness. 



Localities. — Loughshinny, county of Dublin ; near Bantry, county of Cork. (The 

 specimen from the former locality is contained in the Dublin Museum of Science 

 and Art — Geological Survey Collection; that from the latter belongs to Mr. Joseph 

 Wright, to whom I am indebted for the loan of it.) 



G-lyphioceras (Sphenoceras) crenistria, ./. Phillips, sp. Plate XLII, fig. 5. 



1836. G-oniatites crenistria, J. Phillips. Geology of Yorkshire, pt. 2, p. 234, 



pi. xix, figs. 7 9. 

 F 1841. Pal. Foss. Cornwall, Devon, and W". 



Somerset, p. 121, pi. 1, tigs. 234 a — g. 

 ? 1843. F. A. Roemer. Verstein. Harzgeb., p. 33, pi. ix, 



figs. 10 a, b. 

 J. Morris. Cat. Brit. Foss., p. 180. 

 1842-44 A.MMo.MiTKs striatus (pars), L. G. de Koninck. Descrip. Aniiu. Poss. Terr. 



Carl). Belgique, p. 568. 

 1848. Goniatites crenistria, /. H. C ii unit i ng . Isle of Man, p. 357. 



striatus (pars), H. G. Bronn. Geseli. d. Natur, vol. iii, p, 5 IV 

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



p. 115. 



