20 PROCEEDINGS OF THE ACADEMY OF 



interest of which is to be applied to the purchase of books for the 

 library, and ottered the following preamble and resolutions, which 

 were unanimously adopted: 



Whereas, Our esteemed friend, Isaiah V. Williamson, having 

 made a donation to the Academy of Natural Sciences of Phila- 

 delphia of the principal sum of Twenty-five Thousand and Eight 

 Dollars T 4 o<j ( in ground-rent securities) as a permanent fund for 

 the increase of the Library, it is proper that a suitable acknowl- 

 edgment should be made ; therefore, 



Besolved, That the liberal donation made by Isaiah V. William- 

 son, Esq., of Twenty-five Thousand and Eight Dollars T 4 o, as a 

 permanent fund for the use of the library, is of the greatest value 

 in the promotion of science, thereby enabling students of the 

 Academy to pursue their investigations with knowledge of all the 

 information of the age, and that the Society therefore tender to 

 him its most cordial thanks. 



That this fund be named the I. V. Williamson Fund, and that 

 the committee on the library be directed to prepare a suitable 

 book-plate to include a record of the amount and date of accept- 

 ance of the gift, to mark every volume acquired through the I.V. 

 Williamson Library Fund, so that students may know to whom 

 they are indebted for such indispensable aid. 



That the library committee be requested to obtain a portrait of 

 Mr. I. V. Williamson and place it in the library among those of 

 the distinguished philanthropists who have been benefactors of 

 the Academ} r . 



That a copy of the above preamble and resolutions, signed by 

 the officers of the Society, be transmitted to Isaiah V. Williamson, 

 Esq. 



On motion of Prof. Frazer it was 



Resolved, That a committee be appointed by the President 

 which shall seek the co-operation of such scientific men throughout 

 the country as it shall see proper to invite to join them in an effort 

 to have a collection of ores, newer and rarer minerals, and other 

 objects of natural history of the country at the coming Centennial 

 exhibition. 



On (he Homologies of the Sectorial Tooth of Camivora. Prof. 

 Cope made the following remarks on the probable origin of the 

 sectorial tooth. 



The series of dental types which precede the complex struc- 



