128 On Dr. Gerard’s collection of Spiti fossils. [No. 2 
in the characters of the ribbing of the outer whorl, those of the inner 
whorls being exactly similar: the specimens are of the same diameter, 
but while that figured at Plate I. fig. 4, appears to be full grown,* 
that figured at Plate III. fig. 2, is only a fragment, wanting the body 
chamber, and the body-whorl of the former specimen, as is the case 
with many Ammonites and Nautili, is thicker than the inner whorls 
in proportion to their diameter, and exhibits a coarser and wider rib- 
bing, the ribs being rather inclined backwards. A. fissus. Sow, from 
the Oolites of Cutch, bears a general resemblance to the present 
species, but it appears from the description to have the ribs conti- 
nuous across the back. 
5. AMMONITES OCTAGONUS, Strachey, Plate I. figs. 5a—e. 
A. testa discoidea, compressa. Anfr. parum amplexantibus, rotun- 
datis, lateraliter seriebus 3 tuberculis magnis ornatis, irregulariter 
costatis. Apertura elliptica. Septis lateraliter 3-lobatis. 
Allied to Ammonites Hugeni of Raspail, to which species I referred 
it in the first instance. It is ornamented with three rows of promi- 
nent tubercles connected by depressed and somewhat irregular ribs. 
Only one fragment of this Ammonite is in Dr. Gerard’s collection, 
viz., that figured. It does not allow cf my determining the spiral 
proportions. 
6. Ammonites NepaLensis, Gray, Plate I. figs. 6, 6a. 
A. Nepalensis. Gray, Hardwicke’s Illustrations. 
A. testa discoideaé, compressa, complanata, costata ; anfractibus per- 
latis. Costis filiformibus bi-vel tri-furcatis. Ventre rotundato. Um- 
bilico angusto. Apertura compressé elliptica. Septis ? 
Diameter of shell 1 inch 5 lines. 
» of outer whorl Shai 
Thickness 63,, 
2 
Width of outer whorl = ,33, of the diameter of the shell. 
An Ammonite of the Macrocephali type, but more compressed, orna- 
mented with distinct filiform ribs, bifurcating or trifurcating about the 
middle of the whorl, and arched forwards in the ventral region. The 
sutures are not visible. A single specimen occurs in Dr. Gerard’s 
collection. It is much smaller than Dr. Gray’s type, and has a 
somewhat narrower umbilicus. Some large specimens were, however, 
collected by Mr. Theobald. 
* If so, however, the specimen is a small one, as one in Col. Strachey’s collec: 
tion is nearly 4 inches in diameter and one in the British Museum not less than 
6 inches. 
