PLACENTICERATID®. 235 
umbilicus. The gerontic tubercles, together with the ventral line of 
tubercles, make up four rows, one more than appears in any other shell of 
this genus. The sutures were observed only in the anagerontic substage, 
but they are distinctly separated and have obviously not lost their ephebic 
characters. 
There may be but two secondary laterals derived from the primitive 
first lateral saddle, or there may be three; one can not tell with exactitude 
from the drawings and descriptions. The general aspect of this shell is in 
favor of association with the species of Placenticeras, but the extra line of 
tubercles in the old, the fold-like, almost straight coste, and the possibility 
that there are only two secondary saddles, the first and second laterals, make 
the generic reference doubtful. The outlmes of these sutures remind one 
strongly of P. warthi Kossmat, and in this species there is also the same 
difficulty in making out whether the first lateral is single or double. The 
ventral lobe is deep and narrow, as in P. uhligi, but the siphonal saddle is 
small. The shell is apparently smooth in the ephebic stage, as in 
warthi, ete. 
Age: Gault of Cosne. 
PLACENTICERAS WARTHI Kossmat. 
Ammonites orbignyanus Stoliczka, 1866, Pal. Indica, Vol. I, pl. 48, fig. 2. 
Placenticeras warthi Kossmat, 1895, Beitr. Pal. und Geol. Oesterreich-Ungarns und 
des Orients, Vol. IX, pl. 20, fig. 8. 
This species is, as stated by Kossmat, quite distinct either from orbig- 
nyanus of Geinitz, or syrtalis, var. orbignyanus of Schliiter. Kossmat’s text 
clearly states these distinctions, but he gives both of these names in his 
synonymy as in part belonging to this species, and on this fact we differ. 
The young as figured in section by Stoliezka has a very broad venter in 
the ananeanic substage and the broad venter is retained throughout the 
neanic stage. 
The sutures are exceptional, the ventral saddle distinct from any other 
species of this genus, and there are so slight differences between the princi- 
pal lateral saddles and the auxiliaries that one can not, according to 
Kossmat’s figures, draw a definite line between the auxiliaries and the 
principal saddles. Kossmat counts the two arms of the first lateral as two 
saddles, but describes these as having arisen from division of the first 
