468 
Lit. TERES, Holm (Pal. Adh., Dames et Kayser, ili, -hft. i, Pl. v, 
Fig. 5-8). 
Loc., Kandel, Esthland. 
The smooth whorl has in section an abdomen somewhat broader 
than the dorsum as figured by Dewitz and the siphuncle closer to 
the dorsum than in Odini. The living chamber is free and the 
aperture like that of amgulatum. ‘The impressed zone is continued 
to the edge of the aperture. It suffers, however, a certain obvious 
diminution and the dorsal edge of the aperture is merely flattened 
instead af being concave as is the dorsum at the beginning of the 
living chamber. This peculiarity is described by Schroder, who 
gives the best figures. 
Holms’ figures of the young have been copied in outline on 
Pl. vi, Fig. 21-27.. These sections show how closely the young 
resemble those of Schroederoceras Eatont,and if correctly identified 
and drawn indicate considerable variation in the form of the 
young and the relations of the umbilical perforation. In Fig. 
21, it is between the ananepionic and paranepionic ; in Fig. 22, it is 
situated as in Trocholites, viz., carried more on to the metanepionic 
substage, and is differently shaped. 
The young (Figs. 23-27) give a rare opportunity for the study of 
the nepionicstage. The ananepionic substage (Figs. 26-27) is like that 
of Havfont, and one sees the peculiar shape of the apex and the great 
comparative depth of the apical chamber. The first septum and 
czcum of course belongs to the later metanepionic substage, but 
the whorl itself is ananepionic, and this a broad elliptical section as 
seen in the front view of Fig. 26. The dorsum broader than the 
venter and rounded. ‘The shape is here decidedly cyrtoceran. 
The first septum and czecum is seen in this view and the siphuncle 
is subventran. In the metanepionic it changes as in other forms 
towards the centre. ‘This is shown by its becoming extracentroven- 
tran in the third septum, which belongs to the later age of the para- 
nepionic substage. At the angle of the turn a faint, but plainly 
marked dorsal furrow appears. The point at which this im- 
pression occurs is like that of similar forms of early faunas, and 
the shape of the whorls show a very rapid increase of the lateral 
diameters and the usual approximation to the kidney-shaped whorl 
which characterizes rapidly growing shells of Nautiloids at similar 
substages. It seems probable, therefore, that this may have been 
