511 
der anderen Seite, keine eigene, festere, verkalkte Hulle gehabt zu 
haben,’’ If the siphuncle were holochoanoidal, it would have as. 
thick and might have thicker walls than the septa themselves. 
A list of the species is as follows, as given by Notling: A. wndu- 
latum, Boll.; Zorelli, Rem.; Barrandei, DeWitz.; Bolli, Rem. To 
these No6tling has also added Cry. Odini, Eichwald (Lethea Ros- 
sica, Pl. xxvi, Fig. 14a—-6), and he thinks this may be identical 
with wxdulatum. 
Ancistroceras (?) Dyert, n. s., is a large fragment quite different 
from any European species, having the sutures with slight broad 
ventral lobes, slight saddles at the abdominal angles, lateral lobes, 
saddles at the umbilical shoulders, and apparently narrow dorsal 
lobes. 
_ The fragment is that of a rapidly enlarging arcuate whorl, sub- 
quadragonal in section, the lateral zones slightly convergent out- 
wards, the dorsum broader than the venter. 
The siphuncle is ventrocentren. 
The lines of growth seen on the living chamber had the charac- 
teristic ventral sinus, slight crests on the abdominal angles, slight 
lateral sinuses, broad low crests on the umbilical shoulders and in- 
ternally faint minor dorsal sinuses apparently rising to an equally 
faint median dorsal saddle. 
It has characteristics which appear to be intermediate between 
Ancistroceras and Rhyncorthoceras. This fossil is from the Niag- 
ara Group near Chicago, Ill., Dyer collection, Mus. of Comp. 
Zodlogy, and is worth describing in this connection, although until 
it can be studied in the young and figured it is hardly safe to refer 
it to this genus. It has been named Cyrtoceras amplicorne, Hall, 
and closely resembles that species, but the section is more decidedly 
quadragonal, the sides and venter flatter and the transverse diame- 
ter broader. 
Rhyncorthoceras. 
The designation Rhyncoceras has also been used by Remelé and 
others, but Rhyncorthoceras was used first, and should be exclusively 
employed. Rhyncoceras is not an equivalent, and there cannot be 
two names for one genus. . 
Remelé’s description of this genus is perfectly clear and satis- 
factory. It is in my opinion another grade in morphic degenera- 
tion of the Lituitidz, and is directly in line with and supplementary 
