OOLITIC AMMONITES. 
77 
and smooth above, curving forwards towards the umbilicus. 
In style of ornament, the species closely resembles A. Rude - 
sianus, D’Orb., but is of much less rapid growth—a character 
in which it approaches to A. Adelce, of the same author. The 
whorls are more depressed than in either of these species, the 
form of the aperture being transversely elliptical. A. alatus 
is, however, more nearly allied to the Oxfordian than to the 
Liassic members of the group. As represented in the figure, 
Plate 18, fig. 3 a, which is a restoration compiled from two 
fragmentary external casts, it appears like a Crioceras; but 
this appearance is deceptive, and is due to the imperfection 
of the casts, as a fragment of a whorl, fig. 3 b } shows that 
each whorl is slightly indented by the preceding. 
AMMONITES NEPAIENSIS— Gray. 
Plate 14, figs. 1 a-b. 
Ammonites Nepalensis, Gray. Hardwicke’s Illustr., vol. i., pi. 100, 
figs. 1, 2. 
A. testa discoklea, eompressa, costata. Anfract. rotundatis, latis, 
extus compressis, ventre rotundato,—lateraliter complanatis. Costis 
subflexuosis circa 35, validis, per medium anfractus plerumquc 3-fur- 
catis, apud ventrem prorsum arcuatis. Umbilico angusto. Apertura 
ovata, antice eompressa. 
Diameter ... ... ... 4-8 in. Spiral ratio. 2:1 
Ditto of outer whorl ... 2'2 „ Immersion of whorls ... a 
Thickness. 1'9 „ Thickness: diameter ... 
This Ammonite is nearly allied to A. Opis , Sow., which it 
resembles in the width of its whorls, and the number and 
trifurcation of its ribs. A. Nepalensis is, however, more 
tumid, and has broader whorls, and consequently a narrower 
umbilicus than the Cutcli species. The overlap of the whorl 
is considerably greater than is represented in the figures, 
Plate 14, and the aperture or section of the whorl, longer and 
more compressed-ovate than in fig. 1 b. The sutures are not 
visible in either of the specimens examined. 
