1891.] Remarks on Reptiles Called Dinosauria. 449 
in comparison with Iguanodon. The pelvis of these two forms 
can be reduced to the type seen in the Rhynchocephalia and 
Squamata. 
V. THE FORE AND HIND LIMBS. 
The structure of the limbs is of very great taxonomic value in a 
definite animal group of forms; but if we would take the limbs 
alone to establish a system we would be led to the most absurd 
results. The order Enaliosauria was established for the Ichthyo- 
saurs, and Plesiosaurs which are provided with paddles. But this 
is only a parallelism in structure. The Plesiosauria have no re- 
lations whatever to the Ichthyosauria. The same we may say in 
regard to the Dinosauria. The Iguanodon-like forms resemble 
very much the Megalosaurus-like forms; but there cannot be the. 
slightest doubt that this resemblance does not mean affinity, but 
parallelism. 
' VI. ABDOMINAL OSSICLES. 
So-called abdominal ribs were present in the megalosauroid 
forms, as shown by Deslongchamps. They have not been dis- 
covered yet in Iguanodon and Diplodocus, and it is impossible 
to determine with our present knowledge whether they were 
present or not. 
VII. DERMAL OSSIFICATIONS. 
Dermal ossifications are known in the Iguanodon-like forms, 
especially in the highly developed Stegosaurida and Agathau- 
midz; they seem to be absent in the Diplodocus and Cera- 
tosaurus forms. I do not consider such ossifications of great 
taxonomic value, especially not for ordinal characters. 
If we now recapitulate, we have found that the structure of the 
skull and sacrum of Iguanodon, Diplodocus, Ceratosaurus, make 
it sure that these three animals are in no near relation to each 
other ; that they doubtless are the representatives of three different 
groups; that the Dinosauria have to be given up. The question 
‘Now comes up, What names shall we apply to the three groups of 
archosaurian reptiles represented by Iguanodon, Diplodocus, and 
Ceratosaurus ? 
