127, a) being found
in the Carboniferous rocks of Britain, the continent of Europe,
Central Asia, China, India, Australia, Spitzbergen, and North
and South America; whilst _P. Longispina_ (fig. 127, b) has
a distribution little if at all less wide.
[Illustration: Fig. 128.--_Pupa (Dendropupa) vetusta_, a
Carboniferous Land-snail from the Coal-measures of Nova Scotia.
a, The shell, of the natural size; b, The same, magnified;
c, Apex of the shell, enlarged; d, Portion of the surface,
enlarged. (After Dawson.)]
The higher _Mollusca_ are abundantly represented in the Carboniferous
rocks by Bivalves (_Lamellibranchs_), Univalves (_Gasteropoda_),
Winged-snails (_Pteropoda_), and _Cephalopods_. Amongst the Bivalves
we may note the great abundance of Scallops (_Aviculopecten_ and
other allied forms), together with numerous other types--some of
ancient origin, others represented here for the first time. Amongst
the Gasteropods, we find the characteristically Palaeozoic genera
_Macrocheilus_ and _Loxonema_, the almost exclusively Palaeozoic
_Euomphalus_, and the persistent, genus _Pleurotomaria_; whilst
the free-swimming Univalves (_Heteropoda_)are represented by
_Bellerophon_ and _Porcellia_, and the _Pteropoda_ by the old
genus _Conularia_. With regard to the Carboniferous Univalves,
it is also of interest to note here the first appearance of true
air-breathing or terrestrial Molluscs, as discovered by Dawson
and Bradley in the Coal-measures of Nova Scotia and Illinois.
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