1890.] NATURAL SCIENCES OF philadp:lphia. 477 



bell, much new material, intended to illustrate the complete mala- 

 cological fauna, fossil as well as recent, of the United States, has 

 been received, and the hope is held out that before very long this 

 important series may be fully established. 



The department of the Academy which is to-day perhaps most 

 deficient is that of Mammalogy. This department has been in a 

 practically stationary condition for a number of years past; but 

 latterly the generosity of the Zoological Society of Philadelphia, 

 acting under the authority of its able Director, Mr. Arthur Erwin 

 Brown, h^s permitted a number of important lacunae to be filled by 

 the contributionof much important material that could be furnished 

 only by an institution of its kind. Through its assistance the 

 Academy has added very largely to the collections of osteology 

 and comparative anatomy, which are now in a fair Avay to become 

 leading features of the museum. 



Among the donations which it has been the pleasure of the 

 Academy to receive during the past year, is the highly valuable 

 collection of fresh-water sponges made by one of its members, Mr, 

 Edward Potts — without doubt the most comprehensive collection of 

 the kind in the world. It comprises specimens of all the species 

 that have heretofore been discovered or described, and is doubly 

 valuable as being presented by the principal exjwunder in this field 

 of zoological inquiry. 



The type microscopic slides (several hundred in number), prepared 

 by jNIr. Potts in the course of his investigations, are a part of this 

 donation. 



In departments of the Academy not previously specified, the work 

 done has been mainly of a general character. It is a pleasure, in 

 this connection, for the Curator-in-Charge to express his obligations 

 to his able assistant, Mr. J. E. Ives, who continues to render valu- 

 able service in the general care and management of the museum. 



Specimens for study have been loaned during the year to Prof 

 W. B. Scott, of Princeton ; to Dr. G. Baur, of the Clark University, 

 Worcester, and to Mr. Daniel Giraud Elliot, of New York. 



With the view of bringing the Academy into closer contact with 

 its friends and patrons, and to more freely illustrate the nature of 

 its work, it has been thought desirable by many to inaugurate a 

 series of evening gatherings or receptions, at which the representa- 

 tives of different professions and walks of life might meet in social 

 converse. Two such receptions, under the direction of a specially- 



