^ PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 5, 



the association of any given particular modification of the multicuspid 

 tooth with such aerial, terrestrial, or aquatic modification, as the case 

 might be, of the rest of the frame, our conclusion would be an em- 

 pirical one ; and, having regard to the narrowness of its support from 

 observation, would not be such as to leave the mind free from a 

 sense of the possibility of its being liable to be proved to be an erro- 

 neous conclusion. On the hypothesis of the Stereognathus being an 

 Insectivore, there is no known group or form of marsupial or pla- 

 cental Insectivora to which it can be referred. 



The course of observation has shown that the teeth of the smaller 

 kinds of hoofed Herbivora, such as the Peccari, the Hyrax, and the 

 Chevrotains, approach in their cuspidate character, in the smaller 

 amount of the cement, and in the simpler disposition of the enamel, 

 to the form and structure of the teeth in the Insectivora. A nearer 

 approach is made by some still smaller species of extinct hoofed 

 quadrupeds, to which reference has been made in the body of this 

 paper. The shape, disposition, and number of the cusps in the 

 molars of the Stereognathus have appeared to me to be more like 

 those in Microtherium, Hyracotherium, &c., than in any known 

 recent or extinct Insectivore. Just in the ratio of this resemblance, 

 therefore, is the inclination to view the Stereognathus as a hoofed 

 rather than a clawed Mammal; as having been herbivorous rather than 

 insectivorous, and as having been most probably a mixed feeder. 



Physiology, or the known relations of organs to functions, helps 

 me little in this determination : the small degree in which I feel the 

 obligation is limited to the choice of the class : I acknowledge no 

 aid from physiology in any degree of success with which I may have 

 conjectured the nearer affinities of the Stereognathus. Can this 

 example, we have then to ask, be justly cited as showing that there 

 is no physiological, comprehensible, or rational law, as a guide in the 

 determination of fossil remains ; but that all such determinations 

 rest upon the application of observed coincidences of structure, for 

 which coincidences no reason can be rendered? I do not believe 

 this to be the case. 



I feel in the workings of my own mind what I believe to have 

 operated in other minds, an irresistible tendency to penetrate to the 

 sufficient cause of such coincidences — ''to know the law within the 

 law." 



In the ratio of the knowledge of the reason of the coincidences 

 of animal structures — in other words, as those coincidences become 

 " correlations " to my conception — is my faith in the soundness of 

 the conclusions deduced from the application of such rational law of 

 correlations ; and with the certainty of such application is associated a 

 greater facility of its application. A knowledge of the rational law, or 

 of the physiological conditions governing the relations, of the contents 

 of the cavities of bones to the flight and other modes of locomotion 

 in birds, both enabled me to infer from one fragment of a skeleton 

 that it belonged to a terrestrial bird deprived of the power of flight, 

 and to predict that such a bird, but of less rapid course than the 

 Ostrich, would ultimately be found in New Zealand*. The support 

 * Transactions of the Zoological Society^ vol. iii. p. 32. pi. 3,, 



