264 M. A. Wagner on a new Fossil Reptile 
ginning of the tail, whilst the posterior end is broadly rounded, 
and extends considerably beyond the last caudal vertebra.” 
So far this summary report, which thus fully confirms the 
statements of M. Witte, but at the same time furnishes further 
important data for the interpretation of this extremely enigma- 
tical fossil, which I shall now attempt. The business now is to 
ascertain whether this animal, which exhibits at the same time 
characters belonging to birds and reptiles, is to be referred to 
the class of birds or that of reptiles. Let us first consider those 
characters which connect it with birds, and then those which 
unite it with reptiles. 
The most striking resemblance to a bird consists in the clothing 
of the anterior limbs and the tail with feathers. Feather-forma- 
tion is only known in birds. Another characteristic similarity 
to birds is shown by the tarsus, which forms a single bone, but 
has at its lower extremity three processes for the articulation of 
the three toes. This structure occurs in all birds, but has not 
yet been observed in any reptile. 
The characters which do not agree with the type of birds are 
the following :—A divergence of this kind is shown, in the first 
place, even by the feathers themselves as regards their mode of 
attachment. The wing-quills of birds are inserted along the 
whole outside of the hand and fore-arm; in the fossil now under 
consideration, which unfortunately wants the hand, the fore-arm 
shows no feathers; and, moreover, the whole wing is attached 
only to a small bone lying close to the fore-arm, and therefore 
probably belonging to the wrist, from which it radiates like a 
fan. Hqually strange is the mode of attachment of the feathers 
on the tail, from which they issue on both sides throughout its 
whole length uniformly amongst themselves, whilst the rectrices 
on the short tail of birds are only attached to the last vertebra. 
As such a mode of attachment of the feathers of the wing and 
tail is quite foreign to birds, the question finally arises whether 
these fossil feathers are actually identical structures with true 
birds’ feathers, or only present the external appearance of-these. 
The microscopic examination of their structure and the chemical 
investigation of their substance might furnish the most certain 
solution of this doubt. 
The structure of the vertebral column is totally different from 
the type of birds, but, on the other hand, it agrees most closely 
with that of the long-tailed Pterodactyles (Rhamphorhynchus). 
In birds, the sacral and lumbar vertebree, and the nearest of the 
dorsal vertebre, are not only firmly anchylosed together, but 
also, on the outside, covered by the long lumbar sacrum in the 
manner of a roof. In the fossil, on the contrary, the sacral and 
