﻿KIMMERIDGE CLAY. 



87 



The woodcuts, p. 76, Figs. 12, 13, 14/ give the pelvis and hind limb of a Moa (Dinornis) 

 and of a Crocodile (Crocodiles) for comparison with the corresponding parts of a Dinosaur 

 (Omosaurus) : the position, proportions, and structure of the foot of which are guaranteed 

 by those of Iguanodon and Scelidosaurus. 



In the Crocodile the foot may be applied flat to the ground and the thigh turned out 

 nearly at right angles to the body ; but, in some phases of progressive motion, the limb 

 can assume the position delineated : the same may be predicated of the Dinosaurian 

 Reptile. The Bird occasionally rests on the foot, with the metatarsus flat to the ground : 

 but the thigh cannot be turned outward at the angle, which is possible in the Dinosaur 

 and Crocodile. When an accessory trochanter is present in the femur of a Dinosaur 

 {Iguanodon, Scelidosaurus), it projects from the inner border of the shaft, not from the 

 outer one, as in the restoration given in Kg. 3, p. 27, ' Quart. Journal Geol. Soc.,' 

 vol. xxvi, 1870. 



When the question as to the power of predicating homologies both special and 

 general, as in the case of the bones of the vertebrate skeleton, became finally 

 accepted, 2 the hypothesis of the successive incoming of specific forms or modifi- 

 cations of the vertebrate archetype through the operation of secondary causes was the 

 only one which could adapt itself intelligibly to the facts. In enunciating my conviction 

 that ' nomogeny,' i. e. natural laws, or secondary causes, had so operated " in the orderly 

 succession and progression of such organic phenomena," I laid myself open to comments 

 from opposite quarters. On the one hand, the admitted ignorance of the nature and 

 mode of operation of such secondary cause or causes led to the rebuke by a Successor 

 in the chair of the Hunterian Professorship, to wit, that, as to the secondary origin of 

 species, my ' trumpet gave an uncertain sound. 5 On the other hand, an able, theological 

 critic blew the following note of alarm : — It is not German naturalists alone w r ho are 

 contributing to diffuse scientific Pantheism. We have in England an anatomist, Richard 

 Owen. To call him an atheist because of his scientific conclusions would be an imper- 

 tinence ; nevertheless, in a lecture on ' The Nature of Limbs ' which was delivered at the 

 Royal Institution of Great Britain in February last, and has since been published, he 

 brings all his scientific knowledge and demonstrative skill in support of what is called 

 the Theory of Development, and which has become popularly known by its introduction 

 into the book called the ' Vestiges of Creation! This theory of development, as our 



1 The letters have the same signification throughout ; il, ilium ; a, antacetabular plate ; b, post- 

 acetabular plate ; ib (in the Dinosaur) marks the superacetahular plate ; is, ischium ; pb, pubis ; /, femur 

 (of this only the lower part of the bone is given, so as not to conceal parts of the pelvis important in the 

 comparison); t, tibia; b or fb, fibula ; as, astragalus ; ca, calaneum ; cb, cuboides ; i, inner or first toe ; 

 ii, second toe ; m, third toe ; iv, fourth toe ; v, rudiment of fifth toe. 



2 ' Hunterian Lectures,' Royal College of Surgeons, 1844 ; 'Reports of the British Association for the 

 Advancement of Science,' " On the Archetype and Homologies of the Vertebrate Skeleton," 8vo, 1846; 

 and ' Discourse on the Nature of Limbs,' 8vo, 1849. 



