762 J. W. HULKE ON ORNITHOPSIS. 
stance that the Dinosaurian head is not avian, that the only birds 
which showed any vertebral characters in common were Penguins, 
that the fore limb was not avian, and that the avian characters of 
the hind limb were not developed in all Dinosaurs, it would be un- 
safe to infer that Ornithopsis had bird-like lungs; and he thought 
the pits might indicate a lung founded on the type of the Chame- 
leontidee, and therefore be reptilian though bird-like in form. 
Prof. Owen said, In contributing a subject for discussion I am 
sensible of the privilege of submitting it to the Society. To a 
searcher after truth no gift is so valuable as an indication of an 
error into which he may have fallen, or of a wrong direction which 
he may have taken. Such valued return I find to be so constant on 
the part of my fellow labourers Mr. Hulke and Prof. Seeley when- 
ever I venture to submit a paper to the Society, however remote its 
subject may be from that which they criticise, that I am led to look 
upon the circumstance as standing more in a relation of cause and 
effect than of accidental coincidence, and to flatter myself that I am 
not only a contributor, but a cause of contribution in others. The 
considerations involved in Mr. Hulke’s present paper are of two 
kinds, somewhat akin to those which animated the realistic and 
nominalistic disputants of old times. 
There is small likelihood of the generic term Ichthyosaurus 
being superseded by that of Proterosaurus. Yet Home’s claim of 
priority was invalidated by a much less amount of unfitness in the 
term than attaches to Ornithopsis. The vertebree of a Squalus 
maaimus, the limb-bones of an elephant, and both parts of the 
skeleton of an eagle show large unossified tracts. These, in the 
petrified state, are filled with matrix ; but the ossified portions are 
as determinable as in Chondrosteosaurus. The physical question 
therefore is, whether, in the living animal, the unossified spaces were 
occupied by chrondrine, by marrow, or by air. On the latter 
hypothesis the amazement of the beholder of the huge vertebra in- 
dicating the magnitude of the flying dragon may be conceived! 
The inferences from the chondrosal conclusion are tamer, but, in 
my mind, truer. Mr. Lucas’s discovery in the Wealden of Colorado 
of additional parts of Chondrosteosaurus amply demonstrated, as 
Prof. Cope has recognized, its generic distinction from Bothrio- 
spondylus. The neural arch of Hucamerotus, Hulke, is generically 
distinct from that of Camarasaurus, Cope; the cervical centrum of 
Camarasaurus supremus, Cope, is specifically identical with that of 
Chondrosteosaurus gigas, Owen. 
Mr. Hovtxr pointed out that the name Chondrosteosaurus, quite 
as much as Ornithopsis, was founded on theoretical considerations, 
while Lucamerotus was founded on fact. 
