193 
is a deep median furrow, at which the ribs with their tubercles 
end. The mouth-border has a short ventral process. All the 
Fie. 41. Fie. 42, 
Trachyceras Aon. Miinst. 
species are Triassic. Ex. Trachyceras Aon. Munst. (figs. 41, 42,) 
Trach. binodosum, Hav., Trach. Attila, Moss. 
Genus CuoristoceRas, Hauer.—This genus is nearly allied to 
the preceding. The body-chamber is short; the lobes are 
very slightly incised. The inner whorls have their sculpture 
interrupted on the ventral surface, whilst on the last whorl it 
extends uninterruptedly across the abdomen. The structure 
of the lobes shows a persistent relation to an older type, whilst 
in the sculpture on the ribs there is an evident inclination 
towards the Trachyceras type. All the species belong to the Trias 
formation. Ex. Choristoceras decoratum, Havrr, Chor. noricum, 
Moss., Chor. nasturtiwm, Dittm. 
Genus Ruaspoceras, Hawer.—Staff-shaped and tubular, with 
a transverse ring-like sculpture and simple bent lobes; they 
are still very little known, and are probably connected with the 
Choristoceras, to which they stand very near. Rhabd. Suessi, 
Hav. 
Genus Cocutoceras, Hauwer.—The whorls are screw-shaped, 
with continuous ribs and simple bent lobes. This form stands 
also near to Choristoceras; it is found in the Trias beds at 
Zamblach and Salzkammergut. Cochl. Fischeri, Hav. 
