SCIENCE. 



[N. S. Vol. VIII. No. 207. 



The following program was then presented : 



1. H. F. Osborn. On the presence of a Frontal 

 Horn in Aceraiherium incisivum Kanp. 



2. H. F. Osborn. On some additional characters of 

 Diplodocus. 



3. W. D. Mattliew. On some new characters oi 

 Clxnodon and Oxyxna. 



4. W. E. Eitter. On the Ascidians collected by 

 the Columbia University Puget Sound Expedition of 

 1896. Presented by Dr. Dean. 



5. J. P. McMurrich. Erport on the Hexactinise of 

 the same expedition. Presented by Dr. Calkins. 



Professor Osborn described the appearance of 

 an hitherto unrecognized frontal horn on the 

 skulls of Aceratherium incisivum Kaup ; a dis- 

 covery of importauce, as it practically re- 

 moves Aceratherium from the group to which it 

 gives its name and ranges it with rhinoceroses. 

 Professor Osborn suggested that it may possibly 

 be an ancestor of Elasmotherium. 



In discussing the paper Dr. Wortman criticised 

 the common tendency to create types based on 

 a single character, citing in support of his sug- 

 gestion 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 de- 

 scribed the structure of the vertebraj of Diplo- 

 docus, bringing out in considerable detail the 

 variations in the sacrum of the herbivorous 

 Dinosaurs. 



Dr. Matthew briefly described the characters 

 of the teeth, manus and pes of Clsenodon, a form 

 belonging to one of the three families (Arctocy- 

 onidffi) 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. Blatthew regards 

 it as a primitive bear which lived on fruits, 

 honey or other soft foods. Oxyxna, another 

 typical Creodont, was also described by Dr. 

 Matthew, the principal points brought out being 

 the disproportion of the brain case, limbs and 

 lower jaw. 



In the discussion which followed, Professor Os- 

 born showed that while Cleenodon undoubtedly 

 possesses many precocious bear-like structures 

 there are many difficulties to push aside before 

 it can be considered the direct ancestor of the 



bear. There are transitional forms, for example, 

 between dogs and bears, as shown in certain 

 types of teeth (Amphicyon), while, on the other 

 hand, there is a marked difference in the size of 

 the brain of the Arctocyonidse and that of the 

 bears, the brain of the former resembling more 

 closely the brain of the marsupials. If the 

 Amphicyon evidence is of a sufficient phylo- 

 genetic value the bear line must have arisen 

 much later than Dr. Matthew believes. Dr. 

 Lee also questioned the advisability of ascrib- 

 ing particular functions to specialized struc- 

 tures, a criticism which Dr. Matthew met by 

 saying that in this case the relation of structure 

 to funetion was in the nature only of an hypoth- 

 esis, an explanation supplemented by Professor 

 Osborn's statement that in all such cases it is 

 necessary to have some working hypothesis, 

 although each hypothesis is considered merely 

 tentative. 



At the request of Dr. Dean, Mr. Richard 

 Weil was asked to give the main results of his 

 observations on the development of the Ossicula 

 auditus in the Opossum. Mr. Weil finds that 

 both the malleus and incus are derived from 

 the mandibular arch and have no connection 

 with the hyoidean, thus confirming the older 

 German view. 



The other papers on the program presented 

 by Dr. Dean and Dr. Calkins were strictly tech- 

 nical and received onlj' brief mention. They 

 will appear in full in the Annals. 



Gaey N. Calkins, 



Secretary. 



THE PHILOSOPHICAL SOCIETY OF VTASHINGTON. 



The 409th meeting of the Society was held at 

 8 p. m., November 26th, at the Cosmos Club. 

 The first paper of the evening was by E. D. 

 Preston on the International Geodetic Associ- 

 ation Conference at Stuttgart from October 3d 

 to October 12th. The 2d was by Dr. Cyrus Ad- 

 ler on an International Catalogue of Scientifle 

 Literature. The 3d was by Mr. Rene de Saus- 

 sure on the Graphical Determination of Stream 

 Lines. A diagram showing an application of 

 the last paper will be presented at the next 

 meeting. 



E. D. Preston, 



Secretary. 



