REPORT OF NATIONAL MUSEUM, 1921. 95 
continued his descriptive work on American Pleistocene faunas; and 
many other specialists, among whom may be mentioned Ferdinand 
Canu, Versailles, France; Dr. M. A. Howe, New York Botanical 
Gardens; Dr. J. A. Cushman, Boston Society of Natural History; 
Prof. T. D. A. Cockrell, Boulder, Colo.; and Dr. R. T. Jackson, 
Peterboro, N. H., have collaborated by their studies. 
Mr. A. Rodolfo Martinez, of the Geological Institute of Mexico, 
has been working in the laboratory studying methods of mineralog- 
ical and petrological research. 
Distributions —Exchanges predominated in the distributions made 
during the year. These were comprised in 41 shipments with an 
ageregate of 10,250 specimens and 374 pounds of material in bulk. 
Eleven specially prepared lots, comprising 447 specimens, were sent 
out as gifts, and 612 individual specimens, with the addition of 150 
pounds of magnetite, were transmitted in 20 shipments to special 
students and institutions for investigation or experimental work. 
In addition, 23 sets of ores and minerals, 3 sets illustrating rock 
weathering and soil formation, and 3 sets of invertebrate fossils, ag- 
gregating 2,156 specimens, were distributed to schools. 
Total number of specimens in the department.—It is impossible 
to give with even approximate accuracy the number of specimens in 
a collection of this nature. It is estimated, however, that the collec- 
tions of the several divisions yield a total of not less than 1,500,000 
specimens. No statement as to the number of duplicates included 
can possibly be made. 
71305 °—21——_7 
