72 
FOSSIL HEPTILIA OF THE 
Buckland’s Memoir, and suggested that its subject might belong to the same section or 
genusd The subsequent discovery of the skull and dentition has, however, showm that 
another generic section of Pterosauria, or at least one species thereof, had a similar long 
and stiff tail. The modification involving that quality does not, however, extend 
throughout; the anterior caudal vertebrae retain the more normal character, and the 
appendage would be most moveable at its base. No doubt a small degree of yielding at 
the many persistent vertebral joints — for complete anchylosis has not been observed — 
would allow a slight curvature to the extent to which the tail is represented as yielding 
to a lateral force in the restored figure (PI. XX, fig. 2). The number of the caudal 
vertebrae in Pimorphodon macronyx was at least thirty ; the termination of the specimen 
figured in PI. XIX, fig. 4, does not indicate a loss there of as many centrums as would 
bring the number up to thirty-eight, which are assigned by Von Meyer to his Bhatiipho- 
rhynchus Gemminyi. 
As we cannot, therefore, with Soemmerring, insist on the shortness of the tail in some 
Pterosauria as proof that they were Birds, so neither can we conclude from the length of 
the tail in other Pterosauria that they were Reptiles. The legitimate taxonomic deduction 
from such caudal modifications is, that they are not of sufficient importance for determi- 
nation of a class, and that they do not exclusively characterise the genus. They 
indicate adaptations in an extreme and variable part or appendage of the body to special 
powers or ways of movement, or sustentation, in air of the present group of volant animals. 
So, likewise, it cannot be, as it has been, inferred from the length of tail in Archceopferyx , 
that it was a Reptile.^ What we learn from that Avian fossil is akin to what we 
have learnt from Pterosaurian remains, viz., that the tail is a seat of extreme modification, in 
respect of length and number of joints, within the limits of the feathered class. Mamma- 
logists, with a like drift, could add instructive evidence of corresponding caudal variability 
within the limits of the order, as in the volant Cheiroptera, and even within the bounds of 
the family {Bradypus and Megatherium, e.y.). 
The value of the discovery of Archceopteryx, in relation to Pterosauria, is enhanced by 
the peculiar nature of the matrix, conservative of cutaneous as well as of osseous 
characters ; showing casts of down and feathers,® impressions of the fine foldings or 
wrinkles of thin expansions of naked skin, as well as delicate tendons surrounding, 
working, strengthening, and stiffening the caudal framework. 
With these parts the fine lithographic lime-marl should have preserved the plumose 
appendages of the long tail of Bhamphorhynchus, if that flying Reptile had possessed such ; 
and, along with caudal plumes and vertebrae, should have been preserved the bone-tendons 
of the tail, if Archceopteryx had possessed that structure. 
It is probable, from the constancy with which caudal vertebrae of long-tailed 
1 In ‘Leonhard und Bronn’s Neues Jahrbuch fiir Mineralogie,’ &c., Jahrgang, 1857, p. 536. 
2 E. g., as the Gryphosaurus of Andreas Wagner. 
^ A few of the delicate, downy body-feathers of Archceopteryx are clearly indicated near one side of the 
trunk in the slab with most of the bones of the specimen of Archceopteryx in the British Museum. 
