470 
also the form common in the neanic stage of species like Schroe- 
deroceras angulatum and especially Saemanni, which it very closely 
resembles. It is obviously an immature shell of some species of 
this genus. 
SCHROEDEROCERAS EATONI. 
Lituires Eatoni, Whitf. (Bul/. Am. Mus., New York, i, No. 8, 
Pleeaxvis (7); Fig. 5-7 et. Pl. xxx, Migs 15 pot Wigs 
Discoceras Eaton, Schroder (‘‘ Sil. Ceph.,’’ Pal. Adh., Dames 
€t, Kayser, v, p. 22). Pl. vi, Figs. 28-35, and Ply vinjebies 
-8. 
an Fort Cassin, Lake Champlain. 
Having had the original of this species, Iam able to state that the 
_ apex or nepionic stage is closely similar to that of Holms’ figures of 
Schroederoceras (Lit.) teres. The single specimen, Fig. 3s, Pl. vi, 
that showed this section has a large apical or air chamber very deep 
and cap-shaped in outline, with abrupt ventral side, exactly as in 
Holms’ figures, the second chamber being proportionately some- 
what less in depth. The umbilical perforation is, however, much 
larger, as may be seen in this section, and in Fig. 31, Pl. vi. 
The septa continue throughout the first and larger part of the 
second whorl, that is during the nepionic and neanic stages, to be 
proportionately wider apart on the venter and nearer together on 
the dorsum until the dgcrease by growth in the ventro-dorsal 
diameters in the anephebic stage makes them more equal on the 
first quarter of the third whorl where they begin to assume the 
usual depths. The siphuncle begins subventran in the first chamber, 
inclining centrally in its passage through the first and succeeding 
septa until near the end of the first whorl, when it becomes centren. 
It is in other words nearer the venter than the centre during the 
cyrtoceran or nepionic stage and becomes centren in the ananeanic 
substage, as in the figure from Whitfield’s specimen and in other 
figures, Pl. vi. 
The sutures have the usual broad ventral saddles and lateral lobes 
in the nepionic stage and probably dorsal saddles, but these last 
were not distinctly seen. 
The siphuncle in the metaneanic and paraneanic substages trends 
slowly towards the dorsum until the third quarter of the second 
whorl is reached, and after that the approximation proceeds more 
