ce of teeth
in the jaws, and by the still more recent discovery of other
fossil animals (_Pteranodon_) with a Pterosaurian skeleton, but
without teeth; whilst the undoubtedly feathered _Archoeopteryx_
possessed a long tail composed of separate vertebrae. Upon the
whole, therefore, the relationships of the Pterosaurs cannot
be regarded as absolutely settled. It seems certain, however,
that they did not possess feathers--this implying that they were
cold-blooded animals; and their affinities with Reptiles in this,
as in other characters, are too strong to be overlooked.

[Illustration: Fig. 179--_Rhamphorhynchus Bucklandi_, restored.
Bath Oolite, England. (After the late Professor Phillips.)]

The _Pterosaurs_ are wholly Mesozoic, ranging from the Lias to
the Chalk inclusive; and the fine-grained Lithographic Slate of
Solenhofen has proved to be singularly rich in their remains.
The genus _Pterodactylus_ itself has the jaws toothed to the
extremities with equal-sized conical teeth, and its species range
from the Middle Oolites to the Cretaceous series, in connection
with which they will be again noticed, together with the toothless
genus _Pteranodon_. The genus _Dimorphodon_ is Liassic, and is
characterised by having the front teeth long and pointed, whilst
the hinder teeth are small and lancet-shaped. Lastly, the singular
genus _Rhamphorhynchus_, also from the Lower Oolites, is
distinguished by the fact that there are teeth present in the
hinder portions of both jaws; but the front portions are toothless,
and may have constituted a horny beak. Like most of the other
Jurassic Pterosaurs, _Rhamphorhynchus_ (fig. 179) does not seem
to have been much bigger than a pigeon, in this respect falling
far below the giant "Dragons" of the Cretaceous period. It differed
from its relatives, not only in the armature of the mouth, but
also in the fact that the tail was of considerable length. With
regard to its habits and mode of life, Professor Phillips remarks
that, "gifted with ample means of flight, able at least to perch
on rocks and scuffle along the shore, perhaps competent to dive,
though not so well as a Palmiped bird, many fishes must have
yielded to the cruel beak and sharp teeth of Rhamphorhynchus.
If we ask to which of the many families of Birds the analogy of
structure and probable way of life would lead us to assimilate
Rhamphorhynchus, the answer must point to the swimming races with
long wings, clawed feet, hooked