Se S 
Monograph on Dimorphodon. 137 
logical affinities of birds are stronger with reptiles than with 
mammals, the teeth also might be expected, in a bird-ally, to 
have some reptilian characters. But to assert, without evi- 
dence or argument, that the dentition of these animals is rep- 
tilian, seems to dogmatize on a matter against which there is 
actual evidence and theoretical improbability. It can only be 
by suppression of facts that the teeth are named reptilian. No 
one has asserted that they are avian; but the absence of teeth 
from the jaws of Echidna, Myrmecobius, and Balena* among 
Mammals, and from the jaws of Chelonians* among Reptiles, 
is quite consistent with their having allies in which teeth are 
developed ; and similarly the absence of teeth from the jaws 
of birds cannot militate against bird-allies having teeth, i 
such animals existed. If, therefore, it shall be evident that 
Pterodactyles have strong affinity with birds, it would be un- 
philosophical and untrue to speak of the dentigerous mandible 
as Aroi reptilian. 
gives attachment to the lower jaw. In the higher Vertebrata 
Prof. Owen names this bone squamosal ; in some of the lower 
Vertebrata the bone which has that function is named by 
Prof. Owen the mastoid. Hence the difficulty is not with 
Von Meyer, but follows from Prof. Owen's theory of the skull. 
Von Meyer is singularly clear about the relations of his tem- 
poral bone: entering into the brain-cavity as in birds, and 
forming much of the temporal fossa, it is exterior to the parietal 
Squamosal bone. 
z 
d * 
én 
Bird. Pterodactyle. 
* As is well known, teeth have been demonstrated in an early stage of 
life in Balena and Trionyz. 
