598 BRITISH FOSSIL REPTILES. 



Such supposed character seems to have suggested to Von Meyer the name Pachypoda, 

 which he subsequently applied to them, the proportions of the entire foot which would 

 support such tei-m being to him unknown. 



The feet of Dinosaurs are, in fact, characterised by their narrowness or slenderness 

 rather than by their breadth or thickness. The functional toes (hind feet), are, in the 

 typical species of Von Meyer's Pachypoda reduced to three,* and do not exceed four {Sceli- 

 dosaurus, e. g.) in any veritable member of the order. But had Von Meyer known the 

 structure of the Dinosaurian foot, and it had been such as to have been truly defined by 

 his 'family term,' this term must have given way to the "Pachypoda" proposed and 

 accepted in 1821 for a similar group of MoUusca ; as the same term, proposed for a family 

 of Coleoptera, in 1840, had, in like obedience to taxonomic rules, sunk to the condition of 

 a synonym under the law of priority, even when not affected by inapplicability of the name 

 to its objects. t 



Every specimen accessible in 1840, of Megalosaur, Iguanodon, Hylseosaur, having been 

 examined and compared by me and the structure of the sacrum elucidated by observations 

 on its development in birds, J vertebral characters, with dental ones, were substituted for 

 those of the ' Family' above cited from the ' Isis' and ' Palaeologica/ in the definition of the 

 Order Binosauria, quoted by Professor Huxley in his paper on this group. § Of this defi- 

 nition the Professor asserts that " every character which is here added to von Meyer's 

 diagnosis and description of his Pacliypoda has failed to stand the test of critical inves- 

 tigation.'' || This statement is not accompanied with any evidence in its support, but by 

 a suggestion that I had dealt unjustly with von Meyer in proposing the name and substi- 

 tuting the alleged inaccurate characters of the reptilian group Dinosauria. If I have to 

 offer, in relation to the main end and aim of uiy laboui's, any remark which may seem 

 critical, it will be accompanied by its grounds. Thus, in regard to the characters pro- 

 posed by Professor Hu.xley for the Order Dinosauria — 



" 1 . The dorsal vertebrae have amphicoelous or opisthocoelous centra. They are pro- 

 vided with capitular and tubercular transverse processes, the latter being much the 

 longer" (loc. cit., p. 33). 



If by ' amphicoelous' be meant ' biconcave,' as the term ' amphicoelian' has been 

 applied to dorsal vei'tebrse of Teleosaurtis {' Crocodilia,' PI. 4, fig. 6) and of Ichthyosaurus 

 (ib., fig. 7), no such vertebrae exist in the dorsal region of Dinosauria. The term 

 ' amphiplalyan' would more truly express the configuration of the terminal articular 



* E.g. Hyleeosaiirus, 'Dinosauria,' PI. 44 ; Iguanodon, ib., PI. 45. 



j- Pachypus was given to a genus of Coleoptera in 1821 ; this, in like manner, reduced the Pachypui 

 applied to a genus of mammals in 1839 to a synonym. 

 X 'Report on British Fossil Reptiles,' p. 106, 1841. 

 § ' Quarterly Journal of the Geological Society,' vol. x.vvi, p. 32, 1870. 

 II lb., p. 33. 



