ORDER DINOSAURIA. Il6l 



now known to be Sauropodous. The anterior dorsal vertebrae have 

 a well-marked haemal ridge, which disappears in those later in the 

 series. 



Regnosaurus is founded upon a lower jaw from the Wealden, 

 which may pertain either to the last or the following genus. In 

 Polacanthus, of the same beds, we have a remarkable form, in 

 which the dermal armour constitutes a completely solid carapace 

 over the whole of the dorsal aspect of the lumbar region, some of 

 the component scutes being tuberculated, and others ridged ; while 

 there was also a number of detached flattened spines somewhat like 

 those of Hylceosaurus, which probably formed a line in the dorsal 

 region. This peculiar type of carapace forcibly recalls that of the 

 Glyptodont Edentates. In the Chalk-Marl and Cambridge Green- 

 sand, we find Acci7ithopholis with a dermal armour somewhat similar 

 to that of Scelidosaurus, but with rather more complex teeth. The 

 smaller Anofilosaurus, of the Cambridge Greensand, was probably a 

 closely allied, if not generically identical, form ; while the equally 

 small Syngonosaurus and Eucercosaurus, of the same deposits, are 

 distinguished by their compressed and carinated dorsal vertebrae, 

 which resemble those of Hylceosaurus. Apparently allied to these 

 forms is Vecttsaurus, of the Wealden of the Isle of Wight, origi- 

 nally referred to the Iguanodontidtz, but showing the " step " on the 

 transverse processes of the dorsal vertebrae characteristic of the 

 present family. Priodontognathus, founded on a fragment of jaw 

 of unknown age, is probably referable to one of the preceding 

 forms. 



Family Stegosaurid^e. — This family is typically represented by 

 the genus Stegosaurus ; but before mentioning that form it will be 

 convenient to refer to two apparently allied Dinosaurs from the 

 Karoo system of the Cape, both of which are very imperfectly 

 known, and may indicate a family connecting the present with the 

 Igua?iodo7itidce. In Euscelesaurus (more correctly Euscelidosaurus), 

 as the first of these forms is named, the limb-bones were solid, and 

 the femur has a large inner trochanter, and approximates somewhat 

 to that of the Iguanodonts. The tibia and fibula seem, however, 

 to have been more like those of the Stegosauridce ; being anchylosed 

 at their two extremities, and closely joined to the astragalus and 

 calcaneum. The caudal vertebrae, belonging either to this or the 

 next genus, are of an Iguanodont type. The genus Orinosaurus 

 (Orosaurus) was founded upon a bone of a larger reptile, regarded 

 by its describer as the distal end of a femur, but which is really the 

 proximal end of a tibia. Although solid throughout, this bone re- 

 sembles the tibia of Iguanodon in its expanded extremity, and thus 

 suggests a transition between the Iguanodontidce and Stegosauridce. 



The genus Stegosaurus was originally described from the Upper 



