THE PAN-AMERICAN EXPOSITION. 993 
and of the stratum of water immediately above it. These data are 
always obtained at each station where the trawl or other apparatus 
for bottom collecting is used. 
Practically all forms of aquatic life are directly or indirec tly related 
to the fisheries and are therefore appropriate to the work of the Fish 
Commission. In cases arranged around the boundaries of the section 
were specimens of animals which constitute an important, although 
economically small, part of the yield of the various forms of apparatus 
just mentioned. 
An exhibit of oysters illustrated the rate of growth, the modifying 
effects of varying local conditions, the principal enemies, and other 
matters connected with the life history of that important mollusk which 
constitutes by far the most valuable item in the yield of our fisheries. 
Among the other economic mollusca were exhibits of several kinds of 
clams and other species used either as food or bait, or both. 
The crustacean exhibit included crabs, shrimp, lobsters, and related 
forms which are important as food for man, as fish food, or which are 
employed by the fishermen for bait. A number of Porto Rican species 
were shown which do not occur on the coasts of the United States or 
which, occurring, are not utilized as food. 
In the frames immediately above the cases were examples of plates, 
mostly colored, used in illustrating the publications of the Fish Com- 
mission. Above these was a series of charts showing the geographical 
distribution of the most important food-fishes of the Great Lakes, the 
colored areas marking the regions in which the species are known to 
occur. A large map indicated the regions where the Fish Commission 
has carried on scientific investigations. 
A complete list of all the material exhibited under this section may 
be found on pages 306-314. 
DIVISION OF FISH-CULTURE. 
Under this heading were grouped the exhibits which illustrate the 
fish-cultural work of the Commission, embracing full-sized forms of 
apparatus and models of all the appliances used in collecting eggs, the 
hatching of fresh and salt water fishes and the distribution of the same, 
also photographs and drawings showing the different phases of the 
work and the results of fish-culture in certain of the fisheries. 
From the opening of the exposition, May 1, to its close, November 3, 
the practical work of hatching trout, salmon, shad, and pike perch was 
demonstrated. Suitable troughs were provided for the hatching of 
quinnat and other salmon of the Pacific coast, and grayling, brook, 
rainbow, steelhead, and black-spotted trout from the interior waters; 
tables were equipped with automatic jars for hatching shad and pike- 
perch eggs, and cod-boxes illustrated the methods of hatching the eges 
of marine species. On April 30th, 4,000,000 pike-perch eggs were 
received from Put-in Bay, Ohio, and on May 4th another consignment 
