472 ON" AN ALMOST PERFECT SKELETON OE EHTTrSTA. GIGAS. 



Discussion. 



Prof. BoTD Dawejn-s thought the evidence brought forward sup- 

 ported the view that we are still living in the Tertiary period. 

 He thought Ealicore was as highly specialized as Frorastomus. 

 He believed the multiplication of teeth was connected with the 

 aquatic habit. 



Dr. MuEiE pointed out that the characteristics of the whole group 

 of the Sirenia allied them to the Cetaceans, Pachyderms, and pos- 

 sibly the Ungulates. He insisted on the similarity of the skin of 

 the Sirenia to that of the Elephants. The heart, blood-vessels, bones, 

 muscles, and viscera of the Sirenia are all peculiar. He referred 

 to the differences of the tail in different genera of Sirenia. He did 

 not agree with the enumeration of recent and fossil species, as 

 shown in the diagram. He thought that there might be two, but 

 possibly only one, living species of Manatus, and one of Halicore, 

 while many of the so-called species of Halitherium would not stand. 



The Atjthoe, in reply to Prof. Boyd Dawkins, pointed out that the 

 presence of canines and differentiated molars and premolars indi- 

 cated Prorasiomus to be a more highly specialized form. That the 

 multiplication of teeth in aquatic forms is not a universal rule 

 is shown by the edentulous Wiytina. 



