276 
NAUTILOIDEA. 
Cyrtoceras (Meloceras) corniculum^ Barrande, sp. 
1848. Cyrtoceras corniculum, Barrande, Haidinger, Berichte iiber die 
Mittbeil. von Freund, der Naturwiss. in Wien, Band iv. p. 209. 
1852. Cyrtoceras corniculnm, Giebel, Fauna der Vorwelt, Band iii. 
Abtb. i. p. 209. 
1856. Cyrtoceras corniculum^ G. & F. Sandberger, Die Verstein. Nassau, 
p. 145. 
1867. Cyrtoceras corniculum, Barrande, Sjst. Sil. de la Bobeme, vol. ii. 
pt. i. p. 492, pi. cxxi. ff. 1-19, ? pi. ccxvii. f. 3. 
1873. Cyrtoceras corniculum, Salter, Cat. Cambrian and Silurian Foss, 
p. 160. (Figured in the margin.) 
1882. Cyrtoceras corniculum, Blake, British Foss. Ceph, pt. i. p. 173, 
pi. xix. tf . 8, 8a. 
\Not 1860. Cyrtoceras corniculum, Eichwald, Lethaea Rossica, vol. i. 
Seconde Sect, de I’ancienne Periode, p. 1288, pi. xlvii. f. 11. — 
1862. Cyrtoceras corniculum. Hall, Rep. Geol. Surv. Wisconsin, 
vol. i. p. 41, tf. 1, 2.] 
Np. Char. Shell strongly curved, so as to form at least half a 
whorl when the apical part is preserved. The cross section is 
elliptical, the ratio of the ventro-dorsal to the transverse axis being 
about as 4 : 3. The rate of increase is about in the ratio of 2 to 
5 in a length of 40 millim. of the apical part of the shell. The 
length of the body- chamber scarcely exceeds -I that of the entire 
shell. There is a well-marked sinus on the convex border of the 
aperture. The distance between the septa, measured in the central 
part of the shell, is equal to about of the corresponding diameter. 
The siphuncle is situated near to the convex border of the shell, but 
not in contact with the test; its elements are cylindrical. The 
ornaments of the test consist of irregularly-spaced, transverse raised 
lines or narrow bands having an upward imbrication. About the 
region of the body-chamber these bands become coarser, developing 
into folds, a variation frequently met with in these Bohemian 
species^. 
Remarks. The species most closely allied to the present one is 
M. Thetidis, Barr. (pi. cxii.), but it is a larger shell, less rapidly 
tapering, and has coarser ornaments ; it is also less curved and more 
elongated than M. corniculum. Prof. Blake observes that “the 
British species present some little differences from the Bohemian, 
but the reference is probably right.” 
Horizon. Etage E (= Salopian). 
Localities. Lochkow, Kosorz, Bohemia. 
Well represented in the Collection. 
^ See M. cimhiguum, M. decigiens, M. imperiale, &c. 
