NAUTILI!)^. 
281 
The sides of the shell are smooth, excepting around the umbilicus^ 
where prominent folds are developed. Siphuncle unknown. 
BemarTcs. A fragment of the smooth part of the test on the sides 
of the shell, and a portion of the ribbing on the periphery, are 
well preserved o;i the cast above mentioned, which, together with 
another of about the same size, is derived from the Upper Green- 
sand of Devizes. The present species may be distinguished from 
Xauiilus semiundcitiis, its nearest ally, by its more compressed form, 
the finer character of its ribs, and its more flexuous sutures. 
A”, ventroplicatas is represented in the Collection by two large badly 
preserved casts, on one of which, however, as already stated, frag- 
ments of the test remain, sufficient to display its characters. The 
dimensions of the largest specimen are as follows : — Greatest dia- 
meter 11| inches ; greatest width about 8 inches. 
Horizon. Upper Greensand. 
Locality. Devizes, Wiltshire. 
Eepresented in the Collection by two large examples. 
Nautilus Cenomanensis ?, Schliiter. 
1876. Nautilus Cenomanetisis, Schliiter, Cephalopoden der oberen 
deutscheu Kreide, Palseontograpbica, Band xxiv. Abth. ii. p. 168 
(48), Taf. xlv. ff. 1, 2. 
Bp. Char. Shell somewhat compressed, both on the sides and on 
the periphery. Umbilicus open, but not wide. Septa rather 
approximate ; sutures forming a sigmoidal curve upon the sides, 
and descending with an abrupt bend into the umbilicus ; slightly 
emarginate on the periphery. Siphuncle situated between the 
centre and the inner margin of the septa. Surface of the cast in 
the young smooth ; later, rather strong and regular ribs, similar to 
those of Nautilus eleyans, are developed. 
BemarTcs. The specimens which I have, with some hesitation, 
referred to this species, differ in one respect from Schliiter’s form, 
viz., in the position of the siphuncle, which in the latter is described 
as being “ between the centre and the inner side,” whereas in the 
smaller of the British Museum examples (No. 24495) it is central. 
This species is very nearly allied to Nautilus elegans^ but it is 
distinguished therefrom by the flattening of the periphery ; this 
may, however, be a character of only varietal importance. Un- 
fortunately, in the larger of the two specimens (No. 36635) the 
siphuncle cannot be seen. This specimen measures about 9| inches 
in its greatest diameter, and about 5| inches in its greatest width. 
It is all septate. 
Horizon. Upper Greensand. 
