OETHOCERATIDJS. 
19 
Orthoceras Marloense, Phillips. 
1848. Orthoceras Marloense, Phillips, Mem. Geol. Surv. vol. ii. pt. i. 
p. 353, pi. hi. f. 1. 
1882. Orthoceras imbricatum, Blake, British Foss. Ceph. pt. i. p. 153, 
pi. xiy. tf. 1, la, 3, 3a, ? 4, 4a, 5, 6. 
Sjj. Char. Section probably elliptical. Eate of increase varying 
from 1 in 9 to 1 in 15. Septa moderately convex, rather nume- 
rous, about 3 lines apart in a diameter of 22 lines ; somcTvhat oblique 
and undulating. The length of the body-chamber is times its 
basal diameter. Siphuncle subcentral. Surface marked only by 
transverse lines of growth. 
RemarJcs. Phillips’s type is slightly curved, but Professor Blake, 
who appears to have seen it, says that its curvature is due solely 
to the dislocation of the upper part, the lower two-thirds having 
absolutely straight sides.” 
My reasons for reinstating Phillips’s species are given at length 
under the description of Aetinoceras (‘* Orthoceras ”) imbricatum, 
which is retained for Hisinger’s species. 
Horizon. Upper Ludlow. 
Localities. Ludlow, Shropshire ; Kendal, Westmoreland. — A speci- 
men from Llandegfydd, Korth (?) Wales, presented by J. E. Lee, 
Esq., F.S.A., F.G.s! 
Eepresented by several good specimens, one of them figured by 
Blake Qoc. cit.). 
Orthoceras perversum, Blake. 
? 1839. Orthoceras imbricatum, Sowerby, in Murchison’s Sil. Syst. 
p. 620, pi. ix. f. 2. 
? 1852. Orthoceras imbricatum, MUoy, Brit. Pal. Foss. fasc. ii. p. 315. 
? 1873. Orthoceras imbricatum, Salter, Cat. Cambr. and Sil. Foss, 
p. 187. 
1882. Orthoceras perversitm, Blake, British Foss. Ceph. pt. i. p. 165, 
pi. xvi. ff'. 1, 2. 
Sp. Char. Section elliptical. Eate of increase from 1 in 21 in 
the septate portion to 1 in 36 in the body-chamber. The length of 
the latter is more than 2^ times its basal diameter. Septa 
approximate ; distant \ the shell diameter ; irregularly undulating. 
Siphuncle moderate in size, eccentric and unsymmetrical in its 
situation. Surface with lines of growth only. 
Horizon. Wenlock Limestone and Upper Ludlow. 
Localities. Dudley, Worcestershire ; Kendal, Westmoreland. 
Fairly well represented. 
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