202 S. 8S. Buckman—On Jurassic Ammonites. 
The suture-line' of this species differs entirely from Harp. Sirange- 
waysi ; it lacks all the florid ornamentation, the large accessory lobe, 
and the auxiliary lobe; in fact, the suture-line is an almost exact 
copy of what belongs to Hildoceras bifrons. 'The ribs incline more 
to a sigmoidal curve, the inner margin is actually obliquely-truncated, 
and inclining to be concave ; the carina is solid and bounded by two 
slight furrows (which, however, disappear on the body-chamber) ; 
the inclusion is almost nil, and the whorls are consequently narrow. 
The difference betwen the suture-line of Harp. Strangewaysi and 
Hildoceras serpentinum is so striking that any one who has seen the 
two species together would never mistake them. 
fiild. serpentinum is very like Hild. bifrons in all respects, but 
lacks the longitudinal furrow ; while it has smaller ventral channels, 
and its ribs are visible on the inner area. 
The species is evidently extremely scarce both in England and on 
the Continent. I have searched both the Natural History and 
Jermyn Street Museums without success; and the only specimen I 
know is the one in my own collection from South Petherton, pro- 
bably from the Falciferum-zone. 
Neither this nor the previous species were figured in Wright’s 
monograph. . 
Ammonites Murcuisonm, Amm. corrugatus, AMM. LH#VIUSCULUS 
Sowerby ; Harpoceras AMALTHEIFORME, Vacek. 
The first three species have usually been united under the name 
Amm. Murchisone; but this arose from the fact that the two species 
suppressed had never been correctly identified. I was soon able to 
satisfy myself concerning the species to which Sowerby had given 
the name Amm. leviusculus; but the little shell figured as Amm. 
corrugatus proved a most difficult subject. It has in fact taken 
me five years to find the truth, even though I was often able to 
compare Sowerby’s original with my own specimens.? ‘Three years 
ago I imagined that it agreed with the young of Vacek’s species; but 
there was a very slight discrepancy in the curvature of the ribs upon 
the ventral area, and therefore I was not absolutely satisfied. Last 
summer I obtained some specimens from Dundry; and during a 
recent visit to the Natural History Museum, I was able to satisfy 
myself concerning what Sowerby’s corrugatus really was. 
I have already treated of Ludwigia Murchisone, Sowerby sp., in my 
Monograph, pt. i., and have nothing further to add thereto; but I 
will define the other species. 
SONNINIA CORRUGATA (Sowerby). 
1825. Ammonites corrugatus, Sowerby, Min. Conch. pl. 451, fig. 3. 
1867. ————— patella, Waagen, Geogn. Pal. Beitr. (Zone Amm. Sowerby?) 
pl. 25, fig. 2, 3. 
1 Hitherto unknown (Hawg). It agrees almost exactly with my fig. 28, pl. A. 
(Monogr. Ammonites, 1889, part iii.), but the inferior lateral lobe is a little larger 
and is nearer the edge. 
* I take the opportunity of thanking the officers of the Natural History and 
Jermyn Street Museums for their kindness and courtesy. 
