254 
DEVONIAN FAUNA. 
From Euomphalns acuticosta, Sandberger/ wliich equals Eu. Sclmuri, d'Archiac 
and de Vern./ it is distinguished by the presence of the ridge and groove close to 
the suture, and by several other features. 
8. EooMPHALUs FENESTEALis, Whidhome. PL XXV, figs. 1 — 3. 
1841. EuoMPHALTJS SERPENS, Phillips (pars). Pal. Foss?., p. 94, pi. xsxvi, 
fig. 172/ (only). 
1889. — CATENXJLATTJS, Wliidbome (not Sisinger). Geol. Mag., 
dec. 3, vol. vi, p. 30. 
1889. — FENESTEALIS, Wkidbome. Ibid., dec. 3, vol. vi, p. 30. 
Description. — Shell small, flat, discoidal, of four whorls. Apex sunk about 
one-third of the height of the shell. Spire flatly concave. Suture excavate, 
narrow, deep, facing upward, crenulated by the ornament. Whorls increasing 
rapidly, irregularly hexagonal or polygonal in section ; an imaginary horizontal 
plane through the apex almost exactly passing through the suture and the shoulder 
of the shell ; the part of the whorls above this plane being about one-fourth the 
total height of the whorl, and divided into three shallow grooves by two central 
ridges, which are rather closer to each other than to the ridge on the shoulder, 
and to a similar ridge immediately in front of the suture. Ridge of shoulder 
defined above, confluent below. Section of whorl below the above-mentioned plane 
bluntly trigonal, and about two-thirds the height of shell. Ornament consisting 
of small, very elevated, rounded ridges or cords, separated by rather wider, deep 
channels, and swelling almost into nodules on the ridges, rising from the suture, 
crossing the supersutural ridge and inner furrow perpendicularly, bent backwards 
very slightly over the central furrow and very greatly over the external furrow, 
vanishing (almost completely) upon the oblique flat back below the shoulder, and 
becoming very large, prominent, and rounded on the blunt angle and sides of the 
umbilicus. Umbilicus very large, wide, and deep, composed of the regularly 
convex inner sides of the whorls (which are there of a nearly circular curvature), 
divided by a deep linear suture, and ornamented by strong, subangular, prominent, 
elevated, transverse ridges, which are separated by deep furrows, and radiate 
directly on every side straight from the lower side of the nucleus or apex. 
Mouth small, subpolygonal. Shell-structure probably thick. 
Size. — Height 5 mm., width 13 mm. 
1 1853, Sandberger, ' Verst. Rbein. Nassau,' p. 210, pi. x.\v, fig. 2. 
' 1842, d'Arch. and de Vern., ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 364, pi. xxxiv, figs. 7, 
la, lb. 
