AMMONITID&. 79 
appear in the upper Jura of Stramberg, where a considerable 
number of different forms are found. 
The genus (Hcotraustes was created for species of the group 
of O. genicularis, Waagen; Neumayria for such species as O. 
trachynotus and O. Hauffiana, of Oppel. 
HaApLoceras, Zittell, 1870. 
Syn.—Lissoceras and Puzosia, Bayle, 1878. 
Distr.— 76 sp. Jurassic, Cretaceous. AH. ligatum, d’Orb. 
(xxxiv, 49, 50). 
Established for a group allied to Oppelia from the middle and 
upper jurassic, which is characterized by very feeble or no sculp- 
ture ; also some cretaceous forms, as Hapl. Grusanum, are placed 
here; and with them forms very pronounced wedge- or chisel- 
shaped in section, as Hapl. belus ; finally, species with quite sharp 
external sides, as Hapl. nisus, Orb. 
In other jurassic species of Haploceras, there is gradually 
developed a transverse sculpture, which is confined to the external 
side of the body-chamber (Hapl. jungens, Neum., carachtheis, 
Zeuschner). 
In certain upper jurassic forms, which are allied to Hapl. 
carachtheis,the sculpture gradually passes from the external side 
over to the flanks in feebly undulating ribs, as is shown in Hapl. 
cristiferum, Zitt.; better developed in Hapl. wohleri, Opp. ; and 
this feature is repeated in Hapl. difficile, Orb., Cleon, Orb., 
bicurvatum, Leym. 
Finally, species of Haploceras appear which are distributed 
in the cretaceous, with constrictions reaching forwards (Hapl. 
Beudanti, Parraudiert), a peculiarity which does not occur in 
any jurassic form; the inner whorls here serve as sure guides, 
aside from the agreement of the lobular markings, since they 
represent a typical Haploceras- with entirely smooth whorls. 
With these furrows a sickle-shaped undulating radial sculpture 
is gradually combined, and a group of forms results, of which the 
principal type is Hapl. planulatum, Sow. 
In spite of this great manifoldness, it is very easy to distin- 
guish the representatives of Haploceras from strata which are 
lower than the turonian and downwards, by their whole habitus 
and lobes, yet nothing is more difficult to express in words. 
This genus corresponds with Ammonites Ligati of d’Orb. 
Bayle changed the name to Lissoceras, because Haploceras was 
preoccupied by d’Orbigny ; the latter’s species is, however, a 
synonym of Cyrtoceras. 
Stephanocerate. 
Form very variable. Aptychus calcareous, granular, formed 
of two plates, which are sometimes joined at the median line. 
The Stephanoceratz may be subdivided into normal, with regular 
