78 Fossil Eye and Teeth of Ichthyosaurus Australis. 



had more ; it is thus one of the most powerful swimmers 

 of the genus, the species found in European rock having 

 paddles with the phalangeal rows varying from (3) three to 

 nine. The humerus is (5) five inches long, and the width of 

 the distal end is of the two separate articulations, (2) two and 

 (2 1) two and a quarter inches respectively ; the radius and 

 ulna which follow, are each (1J) one and a half inches 

 long, and (2) two and (2-J) two and one eighth wide. 



The teeth as seen in the last specimen presented by 

 Mr. Carson, have a rough bony square base, like those of 

 the I. Campylodon, (Carter), from the Lower Chalk of 

 Cambridge, above which the smooth base of the crown has 

 a circular section ; the rest of the conical crown being longi- 

 tudinally marked with close irregular, obtuse ridges, with 

 much narrower intermediate impressed lines. 



(Professor M'Coy demonstrated the anatomical characters 

 of the specimens in. full, and explained their affinities.) 



Diprotodon. 



The next colossal fossil animal of the country, a previously 

 unknown portion I can bring before you this evening, is the 

 palate and two rows of upper molars of the Diprotodon, lately 

 found in the fresh- water Tertiary Limestone of Limeburners' 

 Point, near Geelong. This specimen has been, presented to 

 the National Museum by Mr. Mercer, through the kind offices 

 of Dr. Day of Geelong. The length of the palate is (7£) 

 seven and-a-quarter inches, arid the width between the 

 premolars is (3-J) three and one eighth inches, and the 

 width between the hind molars is (3 J) three and a half 

 inches. All the proportions of the molars are so nearly like 

 those of the series of molars of the lower jaw of the Diproto- 

 don longiceps, (M'Coy), which I described at a former 

 meeting of the Society, that the present specimen may I think 

 be referred to the same species, and I now lay on the table 

 the plates representing that species for the forthcoming 

 Decades, I am preparing for publication, of the Natural History 

 and Palaeontology of Victoria. An extraordinary character of 

 this specimen is the persistence of the premolars, which form 

 a fifth molar on each side. 



