RECORDS. - 487 



cepted by the section. Professor Frederick S. Lee was unani- 

 mously elected chairman of the section. 



The following programme was then presented : 



1. H. F. Osborn. On the Presence of a Frontal Horn 



IN ACERATHERIUM InCISIVUM KaUP. 



2. H. F. Osborn. On Some Additional Characters of 



DlPLODOCUS. 



3. W. D. Matthew. On Some New Characters of Cl/E- 



NODON AND OxV.ENA. 



4. W. E. Ritter. On the Ascidians Collected by the 

 Columbia University Puget Sound Expedition of 1896. 

 Presented by Dr. Dean. 



5. J. P. McMurrick. Report on the Hexactinle of the 

 Same Expedition. Presented by Dr. Calkins. 



Professor Osborn described the appearance of an hitherto un- 

 recognized frontal horn on the skulls of AceratJierumi inciskmin 

 Kaup ; a discovery of great importance as it practically removes 

 AceratJieriiun from the group to which it gives its name and 

 ranges it with the rhinoceroses. Professor Osborn suggested 

 that it may possibly be an ancestor of Elasmotheritim. 



In discussing the paper Dr. Wortman criticised the common 

 tendency to create types based an a single character, citing in 

 support of his suggestion the considerable variations to which 

 single individuals of a species are subject, and giving one or two 

 instances where errors have occurred. 



In his second paper Professor Osborn described the structure 

 of the vertebrae of Diplodoais^ bringing out in considerable de- 

 tail the variations in the sacrum of the herbivorous Dinosaurs. 



Dr. Matthew briefly described the characters of the teeth, 

 manus and pes of ClcEnodon^ a form belonging to one of the 

 three families, Arctocyonidae, which gave rise to the present-day 

 Carnivora. The structure of the wrist bones in particular brings 

 this form almost within the limits of the Carnivora and Dr. Mat- 

 thew regards it as a primitive bear which lived on fruits, honey 

 or other soft foods. 



Oxycena another typical Creodont, was also described by 

 Dr. Matthew, the principal points brought out being the dispro- 

 portion of the brain case, limbs and low^er jaws. 



