3^ Proceedings of the academy oi* [1886. 



February 2. 

 Mr. John H. Redfield in the chair. 



Twenty-six persons present. 



On a Post-tympanic Ossicle iyi Ursus. -Dr. Harrison Allen 

 called attention to an ossicle in the skull of the bear. It is 

 situated over the point of junction of the squama and the opis- 

 thotic elements as these bones enter into the formation of the 

 mastoid. The bone was seen in the skull of young individuals 

 only. The species examined were Ursus Americanus, Ursus 

 horribilis, and Ursus maritimus. 



The posterior prolongation of the tympanic elements which 

 are so conspicuously developed in 3Iephitis and Taxidea are 

 absent in Ursus. It is every way probable that the new element 

 described is a member of the tympanic series, but instead of 

 being found in the space between the mastoid and the paramastoid 

 it is placed at the tip of the bones which enter into the composi- 

 tion of the mastoid. The name post-tympanic is accordingly 

 proposed for this bone. 



February 9. 

 Mr. Edw. Potts in the chair. 

 Seventeen persons present. 



February 16. 



Mr. Thos. Meehan, Vice-President, in the chair. 



Nineteen persons present. 



The following papers were presented for publication : 

 " On the Minute Structure of Stromatopora and its allies," by 

 Dr. C. Rominger. 



" On the Problem of Reversed Vision," b}' Charles Morris. 



February 23. 

 The President, Dr. Leidy, in the chair. 

 Twenty-four persons present. 



