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PROFESSOR H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
and a distinctive form, but was more nearly comparable with the bone in Solenhofen 
Pterodactyles than in any other kind of animal, living or extinct. # 
It is probable that the bone was supported as an arch, of which the extremities 
met the bodies of vertebrae, and the middle was attached to sacral ribs. In this 
matter we are not entitled to reason from the Hanover and Dresden specimens, 
because they have already been regarded as referable to another, though allied, genus ; 
but the ilium is always broken and more or less displaced, and this favours the view 
that it was arched as in those types. The acetabulum is unknown. The ischium and 
pubis are altogether Pterodaetylian, being expanded bones essentially comparable in 
contours and mode of union, with an obturator foramen between them ; the pubis 
smaller than the ischium, with the ilium extending anteriorly and posteriorly beyond 
both bones. Something of the same type of pelvis is seen among Anomodonts, and 
Fig. 4. 
Nothosaurians and Plesiosaurians show a similarity in the ischium and pubis. It is 
also paralleled among the Cetiosaurian Dinosaurs, and after the Ornithosaurs these 
Dinosaurs would approximate most closely to Protorosaurus in pelvic structure. This 
pelvis is more comparable to the Crocodilian than to the Lacertilian type. So far 
as the ilium is concerned, an approach to this type is made by the Jurassic 
Scaphceosaurus. 
The femur, as already remarked, is Dinosaurian in its straight strong build, 
truncated proximal end, and. distal condyles. If it has not the lateral trochanter 
or the proximal trochanter usual in Dinosaurs, the latter is absent from the femur of 
so typical a Dinosaur as Haclrosaurus, and the former is absent in Stegosaurus and 
some other American genera. 
An approximation to this form of femur is found among Nothosaurians, but those 
animals never exhibit the perfect ossification of the extremities here seen, or distal 
* Seeley, ‘ The Ornithosauria,’ p. 60, 1870. 
