Geological Society. 459 



but now very properly placed in the British Museum, exhibits a 

 jaw similar indeed to the Thylacothere, but belonging to a different 

 genus ; and to this species Mr. Owen has given the name Phasco- 

 lotherium BuckkuuU. Both these generic names imply that the 

 animals are pouched animals ; and in addition to the reasons which 

 led Cuvier to this opinion, Mr. Owen has noticed in the fossils an in- 

 flection of the lower edge of the jaw, which, so far as has been 

 hitherto observed, occurs in Marsupials, and in them alone. 



As if this question had been destined to be settled at this time, 

 the only remaining doubt with regard to the possible existence of 

 double fangs in the teeth of a saurian was removed by the arrival 

 in London of Dr. Harlan with his " Basilosaurus." That gentleman, 

 with great liberality and candour, allowed sections of the fossil to 

 be made in such a manner as to expose the structure of the teeth. 

 And these being examined by Mr. Owen, and compared with the 

 general laws of dental structure which he has lately discovered, it 

 appeared that Dr. Harlan's fossil was by no means a saurian, but 

 an animal nearly allied to the Dugong, to which Mr. Owen pro- 

 poses to apply the generic name of Zeuglodon, expressing the con- 

 joined form of its teeth. 



I have not hesitated to lay before you the view of this subject to 

 which I have been led by the discussions in which we have been 

 engaged, notwithstanding the very great authorities which incline 

 to the other side of the balance. Among these I hardly know 

 whether I am to reckon Mr. Ogilby, who laid before us a very in- 

 structive communication, in which, without deciding the point, he 

 pointed out the difficulties which appear to him to embarrass both 

 views, and especially to contradict the opinion of the marsupial 

 nature of the animal. 



I have dwelt the longer on this controversy, since it involves con- 

 siderations of the most comprehensive interest to geologists, and, 

 we may add, of the most vital importance. For — de sunmid reipub- 

 licce agilur, — the battle was concerning the foundations of our phi- 

 losophical constitution ; concerning the validity of the great Cuvierian 

 maxim, — that from the fragment of a bone wc can reconstruct the 

 skeleton of the animal. This doctrine of final causes in animal 

 structures, as it is the guiding principle of the zoologist's reasonings, 

 is the basis of the geologist's views of the organic history of the 

 world ; and, that destroyed, one half of his edifice crumbles into 

 dust. If we cannot reason from the analogies of the existing, to the 

 events of the j)ast world, we have no foundation for our science ; and 

 you, Gentlemen, have all along been applying your vigorous talents, 

 your persevering toil, your ardent aspirations, idly and in vain. 



Besides the imi)ortant investigations thus referred to, we owe to 

 Mr. Owen other palaiontological contributions. The genus Chccro- 

 potaiiius, established by Cuvier from an imperfect fragment of the 

 bone of a skull, was asserted by him to be a Pachyderm most nearly 

 allied to the 1^'ccari. A fragment of a lower jaw of the same genus, 

 found by Mr. Darwin Fox in tlie Ish- of Wight, confirms this view, 

 but indicates in some points an apjiroach to the carnivorous type. 



