126 On Dr. Gerard’s collection of Spiti fossils. [No. 2, 
dorso-ventral diameter is rather the longer. The angle of the 
phragmacone is about 17°, while that given by M. D’Orbigny 
is 18° to 182°. These differences, however, do not appear to me to 
warrant specific distinction. 
There are several phragmacones of this species in Dr. Gerard’s 
collection. The largest is 2 inches in diameter. The largest guard 
measures as follows :— 
3 in 10 lines long. 
—— 103 ,, lat. diam. 
—-— 10} ,, ant. post. diam. 
Order. TETRABRANCHIATA. 
2. AMMONITES ACUCINCTUS, Strachey, Plate I. figs. 3, 3a. 
A. testa discoidea, percompressa, complanata, subleevigata, obsolete 
flexuoso-costata. Anfractibus complanatis, amplexantibus. Ventre 
sub-acuto; juniori dentato. Umbilico parvo; marginibus rotundatis. 
Apertura angusté hastata. Lobo superiori septorum longiori. 
Diameter of shell linch 8 lines 
if piioutecanionl Tee A fragment wanting the 
Thickness ae body whorl. 
With of outer whorl = ,55, of the diameter of the shell. 
Nearly allied to several Liassic species, viz., 4. oxynotus, Quensted, 
A. lynx, D’Orbigny, and A. Coynarti, D’Orbigny, this Ammonite is 
readily distinguished by the peculiar palmate form of the saddles, and 
the length of the superior lateral lobe as compared with the ventral 
[ quasi dorsal] lobe. The denticulation of the keel is, as in A. lyna, only 
apparent on the young shell, and becomes obsolete with age. The 
sides are faintly marked with ribs curved like those of A. concavus. 
Dr. Gerard’s collection contains two specimens of this species. 
3. AMMONITES STRIGILIS,* n. s. Pl. III. figs. 1, 1a. 
A. testa discoidea, costata, compressé tuberculaté. Anfractibus 
amplexantibus, quadratis. Costis simplicibus, compressis, promi- 
nentibus, anticé inclinatis; apud venter, valdé angulatis. Ventre 
* There is some doubt whether this specimen be really from Spiti, though 
thers is I think but little question that it comes from the north Himalayan for- 
mation. It is one-half of a cut specimen, Another half specimen, (possibly the 
fellow of the above,) is in the British Museum, its locality being also unknown. 
