OETHOCERATID^. 
53 
Horizon. Lower Ludlow (Salopian). 
Locality. Combe Wood, Presteign, Eadnorshire. 
Fairly well represented in the Collection. 
Orthoceras annulatum, Sowerby. 
1816 b OiLhocera annulata, Sowerby, Min. Conch, yol. ii. 1818, p. 73, 
tab. cxxxiii. 
? 1860. Cycloceras annulatum, Eichwald, Lethsea Rossica, yol. i. Second© 
Section de I’ancienne Periode, p. 1229. 
1882. Oiihoceras anniclafum, Blake (pars), British Foss. Ceph. pt. i. 
p. 89, pi. iy. £f. 3, 4. 
Fig. 4. 
Surface ornamentation of Orthoceras anmdatiim and its varieties. 
a, 0. annulattim ; a\ outline of annulations viewed in profile, to show their 
convexity; b, var. crassum\ c, var. Americanum\ d,\ixY. fimbriatum (e, ele- 
vations,/, furrows) ; e, var. subtile. All of the natural size. 
Sp. Char. Shell straight. Section elliptical ; the ratio of the 
diameters 11 to 13. Rate of increase varying from 1 in 10 to 1 in 
14. The length of the body- chamber cannot be accurately deter- 
mined, as the aperture is not preserved in any of the specimens 
examined. 
In one example contained in the National Collection (figured by 
Blake, loc. cit. pi. iv. f. 2), which has been cut longitudinally, the 
portion of the body-chamber remaining is nearly three times the 
length of its basal diameter. The septa vary somewhat in their 
distance apart, being from -J- to | the diameter of the shell. The 
Date of publication of plate. 
