XArTILlDJ']. 
265 
Departement cle TAnbe ; but I have not seen it quoted from any 
other locality." 
Horizon. Gault. Cambridge Greensand. 
Localities. Folkestone, Kent (Gault) ; Cambridge (Cambridge 
Greensand). 
Well represented in the Collection. 
Nautilus Kayeanus ?, Elanford. 
18G1. Nautilus Kayeanus, Blanford, Mem. Geol. Siirv. of India 
Palseont. Indica — i. Fossil Cephalopoda of the Cretaceous Kocks of 
Southern India, p. .31, pi. xvi. ff. 5, 6; pi. xvii. ff. 1, 2; pi. xviii. 
If. I, 2 ; pi. xxi. f. 2. 
1866. Nautilus Neocomiensis, Stoliczka, ibid. p. 210. (^Not of 
d’Orbigny.) 
1879. Nautilus Neocomiensis, II. B. Medlicott and AV. T. Blanford, A 
Manual of the Geology of India, pt i. pp. 272, 274. 
Sp. Char. “ Shell discoid, compressed, ornamented with broad 
undulating ribs, forming an angle on the ventral axis, which is 
rather acute on the young shell and becomes somewhat more obtuse 
with age. The ribs do not appear to increase much in width with 
the growth of the shell, so that in a space equal to the semi-diameter, 
measured on the median ventral line of the shell, they are more 
numerous in adult than in young sj)ecimens ; they are visible on the 
cast of adult specimens as regular sinuous undulations. Umbilicus 
perforated, but not exposing the inner whorls in the perfect shell. 
Ventral area evenly rounded, becoming flattened in the adult shell. 
Aperture ovate. Margins of septa moderately concave, slightly 
sinuous near the umbilicus, arcuated on the sides and straight or 
convex in the ventral region. Biphuncle large, excentric, dorsal, at 
about one-third the height of the septum. 
“ There is some difiiculty in ascertaining the limits of this species 
and the amount of variation to which it is liable, owing to the bad 
state of preservation of most of the adult specimens. The large 
majority of these are argillaceous casts, the shell having entirely 
disappeared, or having been replaced by crystallized gypsum, which 
readily breaks off the cast, and being strongly attached to the 
matrix, rarely exhibits the external ornamentation of the original 
shell. The casts are further frequently crushed, and the shelly 
septa having disappeared, the position of the siph uncle cannot be 
determined, except in a single specimen. 
“The size of the umbilicus in un crushed specimens is tolerably 
constant, but the most striking character, and one by which this 
species may be readily recognized, is the number and approximation 
