242 ’ PSEUDOCERATITES OF THE CRETACEOUS. 
the venter in old age, and apparently the venter retains its ephebic char- 
acters in this old specimen. I can not join Kossmat in considering syrtale 
of Schliiter as identical with this species. The American syrtale shows old 
age at a smaller size than in tamulicum, and the nodes and spines are much 
larger and last longer, especially the median lateral row, but it is much 
closer to this species than to any other European form except schliitert. 
The more compressed form of pl. 48 has the external characters of the 
American lenticulare as figured by Meek, but the sutures are quite distinct. 
Age: Lower Senonian. 
PLACENTICERAS PSEUDORBIGNYANUM n. sp. Hyatt. 
Ammonites syrtalis vax. orbignyanus Schliiter (pars), 1871, Palzeontogr., Vol. SOM, 
pl. 15, figs. 3-5, no others. 
Schliiter’s figure of a typical example of orbignyanus is not similar to 
that of Fritsch and Schloenbach, nor to Geinitz’s species, nor does it agree 
with his var. orbignyanus given on pl. 14. It is a very distinct shell, having 
but one median lateral row of tubercles in the neanic stage. It is otherwise 
smooth and with narrow ventral zone. 
Age: Lower Senonian. 
PLACENTICERAS ? SUBTILISTRIATUM Jimbo. 
Placenticeras ? subtilistriatum Jimbo, 1894, Paleon. Abhandl., new series, Vol. II, 
TOs Bp Tole al, mes, I, Te, 
This is merely mentioned here to call attention to the distribution of 
the genus. It is figured as a young, compressed shell and is certainly in 
aspect like a species of this genus. he figure has a centran trace or keel 
on the venter, although this part is described as being simply convex. 
DIPLACMOCERAS* Hyatt. 
This genus resembles Engonoceras quite closely in its involute com- 
pressed volutions and channeled venter bordered by continuous ridges, and 
in the tuberculation of the sides it is sufficiently near to be included in that 
genus if the sutures were unknown. These are, however, well known, 
thanks to Schliiter’s fine figures, and they appear to be similar to those of 
a AimA6os, double; aku, edge. Misspelled Diplacomoceras in Zittel’s Text-book, Ceph., p. 585. 
