JfATJTILID^. 
189 
septa, probably belongs to a different, though closely allied, species. 
It is characterized by much wider septa than those of the present 
species, and the costae, instead of corresponding nearly with the 
sutures, are situated between them, much as in Plenronautilus dis- 
iinctv.s, Mojsisovics \ to which the fragment under description bears a 
by no means remote resemblance. Other features in this fragment 
are the very acute sinus formed by the sutures upon the periphery, 
and the tendency of the costae to become nodose at the margin of the 
periphery'. Should the discovery of more complete specimens con- 
firm my impression that this fossil is undescribed, I would propose 
that it should be called PJeuronautilus subdisti rictus. 
A species also resembling P. falcatus is the Nautilus Sangamo- 
nensis of Meek and Morthen; but in the latter the sides are con- 
cave, and the ornaments consist only of a row of tubercles at the 
superior lateral angles, there being no costae. The two species are, 
however, very closely allied. 
Honzon. Coal-Measures. 
Localities. Coalbrookdale, Madeley, Shropshire 
Fairly well represented in the Collection. The specimens num- 
hered C. 468 and C. 469 were presented by H. Pearce, Esq. 
Pleuronautilus nodoso-carinatus, F. Poemer, sp. 
1863. Nautilus nodoso-car hiatus, F. Poemer, Zeitschr, der Deutsch. geol. 
Gesellsch. Band xv. p. o77, Taf. xiv. ff. 8, a-c. 
1865. Nautilus {Discites) nodiferus, Armstrong, Trans. Geol. Soc. 
Glasgow, vol. ii. pt. i. p. 74, pi. i. ff. 6, 7. 
1870. Nautilus nodoso-carinatus , F. Poemer, Geologic von Ober- 
schlesien, p. 84, Taf. viii. ff. 19, 20. 
1874. Nautilus nodifenis, IToimg and Armstrong, Trans. Geol. Soc. 
Glasgow, vol iv. pt. iii. p. 280. 
1876. Nautilus nodiferus, Armstrong, Young, and Pobertson, Cat. of 
the Western Scottish Fossils, p. 59. 
Sp. Char. “ Shell discoidal, composed of about three gradually 
enlarging, contiguous, nearly subquadrate whorls, completely ex- 
posed in a moderately shallow umbilicus ; back broad, rounded at 
the edges, and traversed in the middle by a wide and deep channel, 
on the sloping sides of which are two fine thread-like ridges. The 
remainder of the space on the back and sides of the shell is 
^ Die Cephalopoden der Mediterranen Triasprovinz (Abhandl der k.-k. 
Geol. Eeichsanst. Band x.), 1882, p. 278, Taf. Ixxxv. ff. 4a, Ah. 
^ See Prestwich’s ‘ Geology,’ 1888, vol. ii. pp. 92, 93, small type. 
