482 
PROCEEDINGS OF THE ACADEMY OF 
[1890. 
The Section has acquired by 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 obtained, 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. Sampson, 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 pre¬ 
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 faunae 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 completed 
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 space 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 Stomatellidce, Scissurellidce, 
