482 PKocKKi)iN(;.s ok tiik academy of [1890. 



The Section has acquired hy purchase a fine collection of 

 the remarkable fresh-water shells of the African Lake Tanganika. 

 Eighteen species, belonging to thirteen genera, are represented, the 

 number of specimens being over 100. 



The Conservator has also olitained, in exchange from Mr. Robert 

 Jelschin, of Patschkan, Silesia, 100 species of rare land and fresh- 

 water shells, nearly all the species being new to the museum. 



Our extensive suites of American shells have been added to by 

 the donations of Messrs. F. A. Sam})son, O. A. Crandall, John 

 Ford, J. A. Singley, G. H. Ragsdale, E. W. Roper, W. S. Strode, 

 the Conservator, and many others as set forth in the list of acces- 

 sions appended. 



A special collection of the shells of the United States has been 

 commenced under the auspices of the American Association of Con- 

 chologists. It is the intention of the officers, with the cooperation 

 of the large membership of the association, to make this collection 

 a complete exposition of the molluscan life of America. None but the 

 finest specimens of each species or variety are accepted. John H. 

 Campbell, Esq., of Philadelphia, the President of the Association, 

 and the originator of the enterprise, has already received a large 

 number of specimens, 153 trays of which have been placed in the 

 cases, and form an excellent beginning of what promises to be a 

 most valuable addition to the museum. These specimens are pi-e- 

 sented with no conditions save that they shall form a United States 

 collection separate from the general collection and that they be 

 received from members of the American Association of Concholo- 

 gists only. The plan is heartily approved by the Curator-in-Charge 

 of the Academy, as a step toward the formation of special collections 

 illustrating characteristic faume of the globe. 



The museum work has progressed rapidly, and is now as close 

 to the literary part of the work as it can be kept. During the 

 year the entire collection of Helices has been rearranged in harmony 

 with the Manual of Conchology, up to the end of the last comj)leted 

 volume, filling five double table cases and sixty-two drawers, rep- 

 resenting the groups of Helicoid shells included in volumes III, 

 IV and V of the Manual. This work has been rendered possible by 

 the addition to our sj)ace of two double table cases containing six- 

 teen drawers. 



In the current volumes of the Manual of Conchology, the Con- 

 servator has monographed the families Stomatellldce, Scissurellidce, 



