108 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



Collection " may or may not be a portion of the specimen figured by M'Coy ; if it 

 be so it has lost more than half of its original bulk. 

 Local if ij. — Millicent, Clane. county of Kiklare. 



GeH»6— Phacocekas, Hi/att, 1883. 



Phacoceras oxystomum, PhlUlps, sp. Plate XX^"III, figs. 'ia,b. 



1836. Nautilus osTSTOiirs, J. Phillips. Geology of Yorkshire, pt. 2, p. 233, 



pi. xxii, figs. 35, 36. (Not of Trautscbold, 

 Nouv. Mem. Soc. Imp. Nat. Moscou, torn, 

 xiii, p. 304, pi. sxx, fig. 7.) 



1843. — — L. G. (le Koninck. Descrip. Anim. Foss. Terr. 



Carb. Belgique, p. 544, 

 pi. xlii, figs. 3 a, b. 



1844. — (DisciTEs) oxrsTOMus, F. M'Coy. Synop. Carb. Foss. Ireland, 



p. 18. 

 1855. — oxxsTOMTJS, F. irCoi/. British Palaeozoic Foss., fasc. iii, p. 560. 



1860. DisciTES oxTSTOMUS, i2. Griffith. Journ. Geol. See. Dublin, vol. ix, p. 33. 

 1878. Nautilus oxtstomus, L. G. de Koninch. Faune Calc. Carb. Belgique 



(Ann. Mus. Roy. d'Hist. Nat. Belgique, torn, ii), 

 pt. 1, p. 123, pi. xvii, figs. 3 a, h. 

 1883. Phacoceras oxtstomum, A. Hyatt. Genera of Fossil Cepbalopods, 



Proceed. Boston Soc. Nat. Hist., vol. xxii, 

 1882-3, p. 293. 

 1891. DisciTEs (PiiACOCEBAs) OXTSTOMUS, .4. if. ^oorrf. Cat. Foss. Ceph. Brit. 



Mus., pt. 2, p. 99, fig. 12 (about 

 two-thirds nat. size). 

 1893. Phacoceras oxtstomum, A. Hyatt. Carboniferous Cephalopods. Second 



paper. Geological Survey of Texas, Fourth 

 Annual Eeport, 1892, pp. 438, 446. 



Description. — " Lenticular, very much compressed laterally; greatest thickness 

 at the edge of the small shallow umbilicus, from whence the sides slope, almost 

 flatly, to the thin, very acutely carinated periphery; whorls about four, their 

 edges distinctly visible in the umbilicus; the mouth very elongate, lanceolate, 

 embracing three-fourths of the sides of the penultimate whorl. Surface of inner 

 whorl spirally sulcated,^ of the outer turns smooth, or with extremely fine, 

 obsolete transverse lines of growth, having a very strong forward wave in the 

 middle, and a small, slightly marked one at the sloping edge of the umbilicus. 



1 This ornamentation would be more correctly described as consisting of longitudinal (or spiral) 

 ridges, since it is raised above the surface of the test ; M'Coy's term implies a grooved or incised 

 surface. 



1 



