xil INTRODUCTION 
During the winter of 1925-26 Professor Eigenmann, while enroute to Florida 
in vain search of health, mislaid this rough manuscript on board a train. He 
never saw it again, nor resumed work on the collection, his death occurring not 
long afterward, April 24, 1927, after a year at San Diego. The missing papers 
were brought to light by Mr. George F. Scheer, in January, 1928, in a repository 
for lost and found articles in the offices of the Baltimore and Ohio Ry. at Indian- 
apolis. By him they were forwarded to President W. L. Bryan and by him to me. 
During the ensuing summer (1928) I spent five or six weeks making a careful re- 
check of the manuscript with the collections in the Indiana University Museum 
and continuing with the study of parts not covered by the manuscript. 
While working in the Iquitos region I employed as assistant, mayordomo and 
interpreter a Barbado-Peruvian, Percival Morris. With the training which I 
was able to give him, he continued making local collections for a year after my 
departure. These were brought by him personally to New York at the end of 
that time, and form a substantial part of the fruits of the Centennial Expedition. 
Two by-products of the Irwin and Centennial Expeditions, not of ichthyo- 
logical character, should be mentioned: 
Cubé, a fish-poison and insecticide used in the interior of Peru, and discussed 
more at length on later pages, was introduced into the United States, and subse- 
quently has become an important source of rotenone. 
A method of caring for photographic materials in the tropics was designed, 
and improved by more or less accidental discoveries in the field. The method 
was described on my return (Allen, 1922b) and later accounts indicate that it 
has now come into general use. 
The Indiana University collections of Jordan and of Eigenmann were sold 
in the Autumn of 1929 to the California Academy of Sciences, and were removed 
without loss or impairment under the painstaking care of Dr. Barton W. Ever- 
mann, Mr. H. Walton Clark, and Mr. Alvin Seale, to Golden Gate Park, San Fran- 
cisco, where I was able to visit them again in the summer of 1940. 
For a consideration of the regions visited during the Irwin Expedition, con- 
sult Eigenmann, 1922b. The following pages narrate briefly my participation 
in that enterprise, and continue with the story of the Centennial Expedition. If 
Stefansson appropriately designates a certain area of the polar sea as the pole of 
inaccessibility, perhaps I may be permitted to nominate this region east of the 
Peruvian Andes as the Equator of Inaccessibility, the scene of the following ex- 
plorations. 
