56 
NAUTILOIDEA. 
their separation under varietal names. In the present variety this 
difference consists in the very much coarser character of the fimbriae. 
Generally not more than three or four of these lie in the spaces 
between the ribs, whereas in Sowerby’s type, and in other forms 
that should now be associated therewith, the fimbriae number from 
eight to ten in that situation. It should be remarked also that the 
fimbriae are much more distinctly waved in this variety than they 
are in the typical form. These distinctions are exhibited in the 
accompanying figures (p. 53). 
Horizon. Wenlock Limestone, Lower Ludlow ; Aymestry Lime- 
stone, Upper Ludlow (Salopian and Downtonian). 
Localities. British. Dudley, Malvern, Worcestershire; Ludlow, 
Ledbury, Shropshire. — Foreign. Island of Gothland, Sweden ; Buto- 
witz, Bohemia. 
Yar. perundosum, var. nov. 
This variety is conspicuous for the very distinct manner in which 
the transverse fimbriae are waved, the annulations also partaking of 
the same character. The only variety of Orth, annulatum in which 
the annulations themselves are wavy is that one I have called 
Americanum ; but it differs from the present form in the much less 
pronounced character of its annulations, and also in the generally 
coarser nature of its ornamentation. In j^^erundosum there are 10 
or 12 fimbriae in the space between two annulations, or about 16 
if we add those upon one of the annulations. A specimen of the 
apical portion of this variety measui-es 5| inches in length, and its 
greatest diameter half an inch. The sculpture upon it is not very 
well preserved. This is best seen upon a fragment 1| inch in length 
and 1 inch in its larger diameter. 
I am not acquainted with any published figures of this variety. 
Horizon. Wenlock Shales (Salopian). 
Locality. Gaercoed, near Usk, Monmouthshire. 
Yar. Americanum, var. nov. 
1852. Ortliocei'as annulatum?, Hall, Pal. New Y"ork, vol. ii. p. 96, 
pL xxix. f. 3. 
1852. Orthoceras undidatum, Hall, ibid. p. 293, pi. Ixiv., pi. Ixv. f. 3. 
? 1860. Orthoceras annulatum, Roemer, Sil. Fauna des Westlichen 
Tennessee, p. 78, Taf. v. f. 18, a, b. 
1861. Orthoceras nodocostatum, MUhesney, New Palaeozoic Fossils, 
p. 94, pi. ix. f. 5 {Jide J. Hall). 
1863. Orthoceras undulatum, 'BiUings, in Logan’s Geol. of Canada, 
p. 325. 
