Yd. 67.] TEETH FROM THE WEALDEN OF HASTINGS. 281 



rendered to palaeontology by Mr. Charles Dawson, during more than 

 twenty years, in the Wealden formation of Sussex. He commenced 

 his work by obtaining a large series of excellent Iguanodon 

 remains, now in the British Museum ; but, of late, he had devoted 

 his attention to the discovery of minute mammalian teeth. These 

 Multituberculata were a most ancient and widespread type ; indeed, 

 Tritylodon. from the Trias of South Africa (now considered a Therio- 

 dont reptile), was described in 1884 as a primitive mammal by 

 Owen. Charles Moore found Microlestes in the Rhaetic, and Prof. 

 Boyd Dawkins Hypsiprymnojpsis at Frome ; Beckles found many 

 species in the Purbeck of Swanage, and so too Marsh in the 

 Jurassic and Cretaceous of America ; while Cope added the Eocene 

 Polymastodon from New Mexico, and Neoplagiaidax had been added 

 in France. 



The Author, in reply, said he thought that, as the molars of 

 Plagiaulax closely resembled the temporary teeth of the recent 

 OmithorJiynchus, there was still reason to consider the Jurassic 

 genus as Monotreme rather than Marsupial. The new teeth which 

 he had described were essentially Jurassic in type, and so agreed 

 with all the other vertebrates and plants found in the Wealden 

 formation. 



