580 PROCEEDINGS OF THE ACADEMY OF [DeC. r 



family Partulidce, which has been published in the Manual of Con- 

 ch ology. 



Very large accessions of the mollusca of Louisiana and southeastern 

 Arkansas we owe to Mr. Clarence B. Moore. Mr. Stewardson Brown 

 has further augmented the series from Bermuda, and the study of 

 Arizona snails collected by J. H. Ferriss and the Curator has nearly 

 reached completion; reports thereon are now in course of publication 

 by the Academy. 



The shells collected by Mr. A. A. Hinkley in Mexico have been 

 determined, and the new forms described in several papers. 



Mr. John B. Henderson, Jr., has contributed a series of Cuban shells 

 collected this year, and Dr. Arnold Ortmann gave a set of western 

 Pennsylvania freshwater mussels, especially valuable on account of 

 the rapid destruction of the faunas of these streams by mine water. 

 A large series of mollusks from Tonkin has been purchased, in order 

 to afford material for comparison with those of China, Korea and 

 Japan, which the Curator is working upon. 



Accessions hardly less valuable have been received from many 

 correspondents of the Department, as noted in the' Additions to the 

 Museum. 



H. A. PlLSBRY, 



Special Curator, Dept. of Mollusca. 



REPORTS OF SECTIONS. 

 Biological and Microscopical Section. 



The Section has held nine regular meetings during the year, with an 

 average attendance of nine members. Ten informal meetings have 

 also been held. 



The Conservator reports the donation of six boxes of slides from the 

 estate of the late Dr. Henry C. Chapman. 



The work of the year consisted chiefly in the exhibition and descrip- 

 tion of mounted slides and material by each member present, and in 

 the exchange of specimens for mounting, among which may be 

 mentioned a valuable series of about seventy rare minerals in micro- 

 scopic crystals distributed by Mr. Keeley. 



Among the papers presented are the following: "Microscopical 

 Image Formation," by Mr. F. J. Keeley, published in the Proceedings; 

 "The Hookworm Disease," by Dr. T. S. Stewart. 



Mr. Palmer described a new form of Pinnularia which he has named 

 Pinnularia socialis, found in groups of four. 



