263 
Euompiialus catillus, TV. Martin} 
PI. XXTir, Fig. 19. 
ConcliyliolitJniS Ilelicites catillus, W. Marlin, 1809, Pelrif. Derbiensis, p. 18, pi. 17, fig. 
1 , 2 . 
Euonijilialus catilllis, L. Gl. de Koninck, 181.3, Descr. Anim. Foss. Terr. 
Curb. Belg., p. 417, p. 24, fig. 10. 
,, „ Idem, 1873, Eecb. Anim. Foss., II, p. 103, pi. 4, fig. 4 
(for synonymy). 
This is a rather large shell, in the form of a biconcave lens, of which 
the side corresponding to that of the spire may be a little less hollow than the 
opposite side which forms the umbilicus. It consists of seven or eight spiral 
whorls which are in contact but do not envelope each other. The spire is 
bi-carinated, and snbtrapezoidal in section ; its several whorls are externally 
separated from each other by a rattier shallow helicoidal groove following the 
suture. The whole surface is ornamented with irregular lines of groivth 
sufficiently distinct to be visible to the naked eye. The aperture is subtra- 
pezoidal, and nearly as high as broad ; it is bi-sinuous, but the sinus of the 
inferior canal is deeper than that of the superior ; its external margin is sharj), 
prominent, and arched. The umbilicus has the same diameter as the spire, 
and the same form too, except that the spiral whorls are a little less keeled. 
Dimensions. — This species can reach a diameter of sixty-five milli- 
metres, and a height of about twenty-two millimetres. One of the Australian 
specimens has a diameter of thirty-one millimetres only. 
Delations and Differences. — It resembles E. calyx, J. Phillips, but is 
easily distinguished from it by the convexity of the exterior part of the spiral 
whorls comprised between the two keels, by the much greater concavity of its 
spire, and the less regular surface of its umbilicus. 
Horizon and Localities. — This species is not uncommon in the Upper 
Carboniferous Limestone of Vise. It is found in the same limestone in 
Yorkshire, Scotland, and Ireland. Two external casts, one of the spire and 
the other of the umbilicus, were found by Mr. Clarke seven miles N.W. of 
Tilleghary. Prom these two casts I was able to decide the species. 
^ [Mr. E. Etheridge, Jiinr., remai-ks in reference to this fossil — “The shell figured by De Koninck as 
E. caltilus, Martin, a European species, is a very questionable determination, and is probably referable to some 
other genus.” Records Geol. Survey, N. S. Wales, 1896, V, p. 17. — W.S.D.] 
