AMMONITID®. 83 
AcANTHOCERAS, Neumayr, 1875. 
Distr.—36 sp. A. Rotomagense, Brong. (xxxv, 70). 
Shell with a moderately wide umbilicus and not very elevated 
whorls. Margin of aperture and length of body-chamber un- 
known. The sculpture consists of quite straight ribs, which 
become constantly stronger from the suture outwards to the 
external side, which are frequently ornamented with a greater or 
less number of tubercles or nodes, and are most curved in young 
individuals. The development of the external side is very vari- 
able, the middle line sometimes with uninterrupted ribs, some- 
times with a furrow, sometimes with a line of tubercles, the 
elements of which attempt to unite into a keel. Lobular line 
much reduced ; besides the two laterals on the flanks there is at 
most one auxiliary, or a row of two to three extremely small 
deep-lying auxiliaries; bodies of the lobes and saddles plump 
and broad, the last broader than the first, no branching, but only 
a dentation of the lobes. Siphonal and first lateral usually not 
very different in size, the first often larger than the last ; second 
lateral much smaller than the first, both one-pointed. 
SroniczKAtaA, Neumayr, 1875. 
Dedicated to Dr. Stoliczka, of the Geological Survey of India. 
Distr.—8 sp. Cretaceous; India. 8S. dispar, Stol. (xli, 62, 62). 
Forms allied to Hoplites dutempleanus, with expanded body- 
chamber, embracing three-fourths (7?) of a whorl. Margins of 
aperture curved, produced at the middle of the flanks, slightly 
emarginate at the external side. Inner whorls with radial ribs 
which are not interrupted on the external side, and usually here 
attain their maximum strength; body-chamber smooth or with 
thickened ribs; external side without keel or furrow. Lobular 
line branched, consisting of a siphonal, two lateral, and one or 
more less dependent sutural lobes. 
Hoprites, Neum., 1875. 
Syn.—Sonneratia, Bayle, 1878. 
Distr.—50sp. Cretaceous. H. Archiacianus,d’Orb. (xli, 68,69). 
Derived from the group of forms represented by Perisphinctes 
involutus, with moderately narrow umbilicus and high whorls ; 
thickness very variable. Margin of aperture and length of 
body-chamber unknown. Sculpture consisting of divided and 
curved ribs, which originate near the umbilicus or in the middle 
of the flanks in small, thickened, primary ribs or a tubercle ; 
ribs interrupted on the periphery, often separated by a deep 
furrow, or at least feebler at this point; ribs enlarged at both 
extremities, weaker at the middle of the flanks. Lobular line 
complicated, with branches and numerous auxiliaries; lobular 
bodies not very plump; saddles as wide or (mostly) wider than 
