HIND : NEW CARBONIFEROUS NAUTTLOIDS. 101 
Mus., Pt. ii., p. 166, " The umbilical shoulders project in heavy 
ridges." 
CYCLONAUTTLUS, GEN. NOV. 
Nautilus, Wild, 1892, Trans. Manch. Geol. Soc, Vol. xxi., 
PL 3, fig. 17. 
Generic description. — SheU involute, 2-3 whorls, the last 
almost completely covering the others. Umbilicus small, deep. 
The margin, erect and angular in the young part of the shell, 
becomes carried outward so as to present a bevelling of that part 
of the umbilical margin interior to it. 
The chambers are comparatively large. The suture has a 
broad median peripheral sinus with bluntly curved narrow saddle 
at each peripheral margin, along the side of the whorl is a broad 
concave sinus, and an angular saddle at the umbilical margin. 
Observations. — The suture line has a close similarity to that of 
Metacoceras, Hyatt, but this genus has a wide umbilicus, which 
exposes all the whorls and the majority of the species possess 
tubercles at the peripheral margin. The genus is founded on a 
specimen in the Wild collection in the Manchester Museum. The 
specimen was figured by Wild op. supra cit., as Nautilus nov. 
/ sp. The specimen bears a label in Wild's handwriting with refer- 
ence to the figure, and has the name Nautilus cyclostomus on it lq 
manuscript. The figure differs from the present specimen in 
many details. The form of the margin of the aperture, the extent 
of the body-chamber. It does not show the prominent umbilical 
margin, but depicts the inner whorls which are not exposed ia 
the specimen. In spite of these facts judging from the com- 
parison of some of the other figures on the plates with their 
originals, I think there can be no doubt that the figure is intended 
for the specimen I now describe. 
CYCLONAUTILUS UMBIUCATUS, SP. NOV. 
(Plate VI., figs. 3, 3a, 36.) 
Nautilus, nov. sp., Wild, 1892, Trans. Manch. Geol. Soc, 
Vol. xxi., PI. 3, fig. 17. 
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