LIZARDS. 77 



backwards parallel with the ischia, as in birds and Iguanodon, " was by no means 

 universal " among the Dinosauria or Ornithoscelida, as Prof. Huxley preferentially 

 named them. 



Notwithstanding the distinctly recognised lacertilian character of the pelvis of 

 Compsognathus, Prof. Huxley had no hesitation in assigning to this type an erect 

 bipedal method of locomotion. Writing of it in the "Popular Science Eeview," 1866, 

 that illustrious biologist remarks : " 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." 



The silhouette presentment of Chlamydosaurus, reproduced in these pages, 

 forms a not inapt embodiment of the flesh-clad skeleton that must have suggested 

 itself, ghost-like, to the learned Professor's mind. And it is among the author's 

 keenest personal regrets that, through the recent decease of Prof. Huxley, he should 

 have been deprived by so short an interval of gladdening his former teacher's eyes 

 with the sight of a living organism which, if only in the direction of superficial 

 analogy, so nearly realised one, among the many, of his most sagacious inter- 

 pretations of the fossil past. 



A remaining point in the erect running gait of Chlamydosaurus invites brief 

 attention. Such is the construction of the hind foot and its component digits that, when 

 thus running, the three central digits only rest upon the ground. As a consequence 

 of this structural peculiarity, the track made by this lizard when passing erect over 

 damp sand or other impressible soil, would be tridactyle like that of a bird, and 

 would also correspond with the tracks that are left in Mesozoic strata by various 

 typical Dinosauria. This tridigitigrade formula of the gradation of Chlamydosaurus, 

 induced by the great relative shortness of the first and fifth digits, is distinctly 

 indicated in fig. 1 of the Plate previously referred to. 



Whether or not the bipedal locomotive comportment of Chlamydosaurus has 

 been transmitted by heredity from a lizard-like Dinosaurian such as Compsognathus, 

 or has been re-developed independently among its allocated family group of the 

 Agamidce, is a question concerning which it would be unbecoming temerity on the 

 writer's part to pronounce a verdict. The phenomenon, while dominant among the 

 Reptilia of bygone ages, is, with the exceptional instance afforded by Chlamydosaurus, 

 apparently extinct among living types, and is, on that account alone, of unique 

 interest. 



