126 
BULLETIN OF THE UNITED STATER FISH COMMISSION. 
digested. The longer the time since leaving salt water, the more the digestive 
organs become contracted. 
The figures on pages 126-128 illustrate the successive changes in the alimentary 
canal as observed in specimens from Monterey Bay, head of Snisun Bay, Sacramento 
River at Sacramento, and at Battle Creek fishery. 
Stomach, pyloric appendages, and part of intestine of two female salmon taken in Monterey Bay, Cal., drawn to 
same scale. A , July 6, 1900, stomach containing food. B , July 10, 1900, stomach empty. 
The skin . — The most immediate change noticeable in the salmon after leaving 
the ocean is the great increase in the amount of slime that exudes from the skin 
upon removal from the water. This point is of physiological interest, but lias 
not yet been studied. By the time the fish reaches the spawning-grounds the skin 
in most cases has thickened considerably, and frequently the scales are entirely 
embedded and invisible. In the upper figure of plate 13 the scales can be seen only 
where the skin has been worn off. 
