vill 
strong concentric strie, as well as transverse ones ; in ours we 
have only seen them on the young part of the shell, and there 
they are but faint. It is tobe regretted that we cannot see the 
outer edge of the septum in our specimen ; it is most probably 
a little curved back, as in both the American species of Tro- 
cholites. 
Loe.—The Cymmerig brook, Bala; Bryn Eithin, Caernar- 
yonshire ; in Cambrian rocks. 
L, coRNU-ARIETIS, Sow. 
Syv.—ZL. perfectus, Wahl. Act. Soc, Reg. Upsal. Vol. VIII. p. 83. 
L. lituus, His. Leth. Suec. t. 8. fig. 5? L. cornu-arietis, 
Sowerby, in Sil. Syst. Pl. 20. fig. 20 (not fig. 18). 
Sp. Ch.—Discoid, whorls three or four, close at first, but not 
indented by each other: afterwards produced and straight ; 
crossed by numerous slightly-raised coste, with close wavy 
lines of growth between them and parallel to their direction, 
which is backward, in a curved line. 
I have not referred to Lituites cornu-arietis, var. p. Sil. 
Syst. Pl. 22. fig. 18; for there is much doubt whether that 
regularly ribbed shell be at all the same ; it seems much nearer 
to L. giganteus. 1 cannot help believing our fossil to be iden- 
tical with Wahlenberg’s, especially as ZL. cornu-arietis does 
occur in Norway. There are specimens of it in Sir R. I. Mur- 
chison’s cabinet. 
Loc.—Coniston, in Cambrian rocks. 
L, ancurrormis, Sp. Nov. Pl. 1. L. fig. 26. 
Sp. Ch.—Smooth, with obscure lines of growth ; whorls not 
indenting each other, elliptical, the shorter diameter in the 
thickness ; each whorl about twice the width of the preceding ; 
APPENDIX A. 
| septa concave, close, their lateral edge curved deeply back, 
across the whorl, then passing straight across the periphery, 
so as to truncate the concave cup formed by each septum ; they 
are directed obliquely back, so that the inner margin of the 
septum is more forward than the outward one; siphuncle 
moderately large, close to the inner margin. ‘ 
The very faint strie on the shell are somewhat distant, and 
are-curved backward, as in L. cornu-arietis, but they do not 
interrupt the smoothness of the surface. 
The Clymenia levigata, Miinst., from the limestone of Schu- 
belhammer much resembles our fossil, although quite distinct 
from it in the form of the septum. In that species, as in ours, 
the septa curve simply back ;—but instead of passing straight 
across the dorsal margin they curve slightly forwards. C. levi- 
gata and its allies from the same locality differ widely too from 
other Clymenie, by wanting the lateral notch or sinus in 
the septum. And our shell and the Lituites Odini, De Vern., 
seem only a step removed from these forms, by having the 
septum edge straight across the back. L. undosus (Nautilus, 
Sow.) goes a step farther, and has this line again curved back 
alittle, so that the meeting of the lateral curve with the dorsal 
one leaves a projecting angle on each side the outer edge of the 
septum. Then in T'rocholites, the American inyolute form of 
Lituites, this"backward curve is enlarged, and becomes almost 
a dorsal sinus. And lastly, in an unpublished form of this kind 
in the Cambrian rocks of Ireland, the dorsal sinus is complete, 
and a decided approach made to such paleozoic forms of Nau- 
tilus as NN, clitellarius of the coal strata. 
Loc —Limestone of Mynydd Fron-frys, in the Glyn Ceiriog, 
S. of Llangollen, Cambrian rocks. 
