Annals of the Transvaal Museum 
17 
quently a quite different shape. The external saddle of the lobe-line of H. 
amapondensis is quite different to that in H, quadrinodosus. The relation of the 
breadths of the external saddle and the first lateral saddle in H. quadrinodosus 
is quite different to that in H. amapondensis. The median secondary saddle 
in the first lateral lobe is narrow in H. amapondensis and broad in H. quadri- 
nodosus. 
The differences in the lobe-line, in connection with the difference in shape 
and with the probable differences in ornamentation, are apparently sufficient 
to regard the Pondoland specimens as belonging to a new species. 
Genus HETEROCERAS d’Orbigny. 
Heteroceras amapondense n.sp. PI. IV, figs, i, 2. 
Shell spirally and dextrally wound; spiral vector long. Whorls in contact 
with each other. Last whorl bent backwards over the others in the direction 
of the apex of the shell. It is in contact with the penultimate whorl, but not 
with the whorl preceding this. Section of whorl somewhat elliptical, the long 
axis of the ellipse practically vertical on the spiral vector. In the young speci- 
men present the section of the whorl is practically circular. The increase in 
size of the whorls is slow. 
Whorls ornamented with numerous smooth, simple ribs, which are placed 
slightly obliquely. These ribs are broad at the base and very high on the external 
side of the shell; on the internal side they are fine, low and thread-like. The 
transition takes place on the upper surface of the whorl and is very rapid. On 
passing from the upper surface inwards the ribs also bend forwards. This, 
however, is only visible on the first whorl; in the second whorl this portion is 
covered by the first. In a very small specimen this forward bend is present, 
although much less pronounced than in the type, on its early end ; on its later 
end the bend has nearly disappeared. In another, larger specimen this bend 
is also less conspicuous than in the type. On the first whorl present all ribs 
are of uniform size, but on the second, that is the last whorl before the irregular 
end and also on this end, one of the ribs, at irregular intervals, is very much 
larger than the others. The intervals present between the large ribs of the last 
whorl contain 7, 9 and 6 small ribs respectively, while the five intervals on the 
irregular end contain 3, 4, 3, 2 and 3 ribs respectively, and therefore the large 
ribs are closer together towards the end. The edge of the ribs is not sharp but 
broadly rounded in the large ribs and flattened in the small ones ; the edges of 
this rounded or flattened surface stand out over the sides of the rib. The 
greatest height above the general surface of the shell of one of the large ribs, 
which is complete, is nearly 3 mm. For the greater part only the cast of the 
specimen is present and the ribs of the cast are much lower than those of the 
shell. 
The lobe-line is not visible and it was not thought advisable to develop it 
on this specimen. However, a fragment, which is indistinguishable from the 
large specimen, shows portions of its lobe-line; these portions agree essentially 
with the lobe-line given by Woods ( 17 , PI. XLII, fig. 5 c) of Heteroceras sp. 
I did not find any difference between this species and the two Heteroceras sp. 
and the Hamites {Anisoceras) sp. described by Woods ( 17 , p. 339, PI. XLII, 
figs. 4, 5, and p. 340, PI. XLIV, fig. 3). From our specimen it is apparent, that 
the presence of stronger ribs here and there is a question of age, and because 
of their presence on one whorl and absence from another in the same specimen, 
this character cannot be used to separate fragments specifically. 
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