In this
genus, the shell is spirally curved, the septa are strongly lobed
or angulated, though not elaborately frilled as in the Ammonites,
and the siphuncle is dorsal. In addition to _Goniatites_, the
shells of true _Ammonites_, so characteristic of the Secondary
period, have been described by Dr Waagen as occurring in the
Carboniferous rocks of India.
[Illustration: Fig. 129.--_Goniatites (Aganides) Fossoe_.
Carboniferous Limestone.]
[Illustration: Fig. 130.--_Amblypterus macropterus_. Carboniferous.]
Coming finally to the _Vertebrata_, we have in the first place
to very briefly consider the Carboniferous _fishes_. These are
numerous; but, with the exception of the still dubious "Conodonts,"
belong wholly to the groups of the _Ganoids_ and the _Placoids_
(including under the former head remains which perhaps are truly
referable to the group of the _Dipnoi_ or Mud-fishes). Amongst the
_Ganoids_, the singular buckler-headed fishes of the Upper Silurian
and Devonian (_Cephalaspidoe_) have apparently disappeared; and
the principal types of the Carboniferous belong to the groups
respectively represented at the present day by the Gar pike
(_Lepidosteus_) of the North American lakes, and the _Polypterus_
of the rivers of Africa. Of the former, the genera _Paloeoniscus_
and _Amblypterus_ (fig. 130), with their small rhomboidal and
enamelled scales, and their strongly unsymmetrical tails, are
perhaps the most abundant.
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