XAUTIUD^. 
165 
dorsal [close to the periphery]. Shell smooth or ooly marked with 
strim of growth.” {cVArchiac and de Verneuil.) 
Remarks. There is only one species with which this may be com- 
pared, viz. the Gyroceras hinodosum of G. & P. Sandberger \ but this 
differs essentially from Centroceras tetrayonum in its ornamentation, 
which consists of two rows of transversely elongated nodes or 
tubercles situated on the peripheral angles and separated by a 
narrow median ridge. The septa are also wider apart in Sand- 
berger’s species than they are in the present one. The siphuucle is 
similarly situated in both. 
Horizon. Middle Devonian. 
Locality. Gerolstein, Eifel. 
Represented in the Collection by a single example, figured 
above (p. 163, fig. 26). 
Genus SOLEN^OCHEILUS, Meek and Worthen", emend. 
Hyatt 
{Cryj^oceras, d’Orbigny, 1810 •*; Asymptoceras, Pi 3 Tkholt, 1852 ’; 
Nautili Globosi (pars), de Koninck, 1878®; Gnippe des Nautilus Rar- 
randei," Mojsisovics, 1882 Asymptuceras, Hyatt, 1888®.) 
The description of Solenocheilus hy ^leek runs as follows : — 
“ Shell generally presenting the form and surface characters of 
Nautilus proper, but with siphuncle very nearly against the peri- 
phery, and the lip on each side drawn out into a narrow spout-like 
projection. 
“ Type, Nautilus {C ryjjtoceras) Sprinyeri, AYhite and St. John.” ® 
Carboniferous. 
1 Die Yersteinerungen des Ebeiniscb. Schichtensyst. in Nassau, 1856, p. 135, 
Taf. xii. ff. 4 a-4 c. 
^ Proceed. Acad. Pat. Sci. Philadelphia, 1870, p. 47. Also United States 
Geol. Surv. Terr. 1876, vol. ix. p. 491, from which the description of the genus 
given here is taken. 
® Proc. Boston Soc. Pat. Hist. 1883, vol. xxii. p. 296. 
^ Prodr. de Paleontologie Stratigraphique, vol. i. p. 114. 
’ Police sur les Genres Nautilus, Vestinautilus, Asymptoceras, &c., p. 6. 
® Faune du Calc. Carb. de la Belgique (Ann. du Mus. Roy. d’Hist. Pat. de 
Belgique, tom. ii.), pt. i. p. 90. 
Die Cephalopoden der Mediterranen Trias-Provinz (Abhandl. d. k.-k. geol. 
Reichsanst. Band, x.), p. 288. 
® Op. cit. p. 296. 
® Trans. Chicago Acad. 1868, vol. i. p. 124. Springeri is curiously mis- 
printed spiniger in Meek’s Report on the Invertebrate Cretaceous and Tertiary 
Fossils of the Upper Missouri Country (United States Geol. Surv. Terr. vol. ix. 
p. 491). 
