FT, 2.] 
Stoliezka. Cretaceous Cephalopoda. 
33 
the two original specimens of Prof. Forbes is the small number of septa, one of the specimens 
having 10 and the other 12 of them, while of two specimens of N. daideus from Riigen, in 
the Geol. Soc. collection, one has 16 and the other 18 septa. I have compared all our avail¬ 
able specimens of this species, and I find that the number of the septa appears greatly to 
vary. Inflated specimens usually have a smaller number of septa, as few as 10 in one circuit, 
but this number always increases in somewhat greater proportion with the size of the shell; 
more compressed specimens usually have 16—20, but occasionally as many as 24 septa, these 
being arranged much closer to each other the more they approach the body whorl. 
A MMONITIDJE. 
AMMONITES, Auctorum. 
Ammonites Blanfobdianus, Stoliezka, Ceph. 1. cit., p. 46. 
This species is closely allied to some of the compressed varieties of Am. various, but 
always distinguished from it by a much narrower back, higher and serrated keel; the septa 
are in both species almost identical, but appear to be a little less serrated in the Indian fossil. 
Am. various and Coupei stand in about the same relationship to each other as do 
Am. Mantelli and Am. navicularis. 
Ammonites bosteatus, Sowerby ; Am. inflates. Sow., Ceph. 1. cit., p. 48. This last 
name must be replaced by the former, inasmuch as it is not only more characteristic, but also 
has priority, the species having been first figured and described under the above name. 
Ammonites Siva, Forbes, Ceph. loc. cit., 39. The terminations of the saddles of this 
species are phylliform, exactly as in the Heteeopuylli, for which Suess proposed the 
name Phylloceras. 
Ammonites Ebmbda, Forbes, Ceph. loc. cit., p. 63. 
One of Forbes’ specimens of Ammonites Dwrga is a young shell of this species, having 
the upper layer of the shell removed and the keel therefore obsolete. The specimen figured 
by me (loc. cit., pi. 71, fig. 6) as a young specimen of Am. Furga also belongs to 
Am. Fembda. 
Ammonites idoneus, Stoliezka, Ceph. loc. cit., p. 64. 
Another specimen apparently of this species has been subsequently found in the greyish, 
siliceous sandstone from near Andoor. It is about the same size as the one figured on 
plate 36, but has no trace of tubercles, the transverse ribs becoming, however, somewhat 
obsolete at the centre of the back. It is also slightly irregularly coiled at the inner edgo 
of the umbilicus, giving the shell an appearance of a young Sea-plates. 
Ammonites vicinalis, Stoliezka, Ceph. loc. cit,, p. 84, pi. 44. 
It is, as formerly stated, very doubtful whether this species is distinct from Amm. Saxbii, 
Sharpe. I have compared the original of the English fossil, which in general character fully 
agrees with the Indian species, merely differing from it by a larger number of intermediate 
shorter ribs and a more squarish section of the whorls, while all our specimens of Amm. 
vicinalis are conspicuously compressed towards the back. Until more and better pre¬ 
served specimens of the English species have been found they cannot be pronounced to be 
identical; the outlines of the lobes are in both the same. 
Ammonites dispaii, d'Orhigny, Ceph. loc. cit., p. 85. 
I have seen a specimen of this species in a collection of fossils of the Hanoverian 
cretaceous deposits in the Museum of the Mining Institute at Berlin. 
Ammonites guadalocp/e, Iiomcm, Ceph. 1. cit., p. 90. 
Romer’s original specimen, which is in the University collection at Bonn, is rather badly 
preserved; it has the umbilical tubercles somewhat more distantly placed from the suture, 
than in most of our specimens, but this does not appear sufficient to be a specific distinction 
between them. 
Ammonites Obbignyanus, Geinitz, Ceph. loc. cit., p. 92. 
Young specimens of this species have a few small, sharp tubercles at the edge of the 
umbilicus, and the lateral ribs being strongly flexuous on the outer half of the whorls become 
