OCR Text |
Show 1895.] PRILLED LIZARD OF TROPICAL AUSTRALIA. 719 differed from any other Dinosaur previously described," was associated with the circumstance that " its tail was quite slender and flexible, and evidently usually carried free from the ground." It is further worthy of note that in Marsh's figure above quoted the pelvis of Anchisaurus is represented as corresponding more nearly with that of existing Eeptilia than with that of the more typical Dinosauria. The prolongations of the ilia in front of the acetabula are relatively short, while the pubes are directed distinctly downwards and forwards like those of all ordinary Lacertilia. The Dinosaurian type most worthy of attention in correlation with Chlamydosaurus is the Compsognathus longipes of A. Wagner yielded by the lithographic stones of Soleuhofen. An admirable cast from the type specimen, which is almost perfect, is also on view in tbe Geological Department of the Natural History Museum. In size, in the slender character of the entire skeleton, and in the relative proportions of the fore and hind limbs, it is almost a counterpart of Chlamydosaurus kingi. In a notable essay, entitled " Animals which are most nearly intermediate between Birds and Beptiles," contributed to the ' Popular Science Review' in the year 1866, the late Professor Huxley makes a special reference to Compsognathus. He says in allusion to it,"It is impossible to look at the conformation of this strange Reptile and to doubt that it hopped or walked in an erect or semi-erect position after the manner of a bird, to which its long neck, slight head, and small anterior limbs must have given it an extraordinary resemblance." Referring to tbis same type in his 'Anatomy of Vertebrated Animals,' ed. 1871, p. 262, Professor Huxley remarks :-" The pubes of Compsognathus, unfoi'tunately obscured by the femurs, seem to have been very slender, and to have been directed forwards and downwards like those of Lizards. Some Lizards in fact have pubes which, if the animal were fossilized in the same position as Compsognathus, would be very similar in form and structure." And again on page 2 6 3 : - " It remains to be seen now how far the Hypsilophodont (Avian) modification of the pelvis extended among the Ornithoscelida (Dinosauria). The remains of Compsognathus and Stenopelyx tend to show that it was by no means universal." All things considered, Chlamydosaurus would appear to present, in virtue of its erect gait, as distinct a divergence from among the Lacertilia in the direction of certain of the Dinosauria, as do some members of the last-named group towards that of the ordinary Lizards, leaving between the two a by no means immeasurable hiatus. Whether or not the remarkable locomotive comportment of Chlamydosaurus here recorded has been transmitted by heredity from a lizard-like Dinosaurian ancestor, such as Compsognathus, or has been redeveloped independently among the Agamidae, may be commended to the consideration of the herpetological expert. 46* |