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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
IV.— ADULT STAGE. 
I have found a large Dibothrium in the white pelican {Pelecanus erythrorhynchus), 
which is evidently the adult form of D. cordiceps, of which the trout {Salmo mylciss) is 
the intermediate host. 
Of the four birds examined, two contained this parasite. These were situated 
about the middle of the intestine. They were in several fragments in each case, but 
there was no tendency shown to separate into individual proglottides. Some of the 
fragments were slender and attenuated, and when studied subsequently proved to be 
the older parts of the strobiles degenerated into slender ribbons of connective tissue 
and still containing eggs. In one of the birds, the length of the fragments, which 
evidently belonged to a single strobile, was about two meters. There was in addition 
to this an approximately equal amount of attenuated fragments of degenerated por- 
tions of the strobile. 
The fine impression made by the stately movements of the pelican while on the 
water or in the air is not sustained on closer acquaintance. It has an abominably 
rank and fishy smell. It is grievously tormented with parasites. The alimentary 
canal of an adult bird is from 2 to meters in length, and throughout its whole 
extent it is liable to be infested with various parasites. Least numerous and least 
painful are the dibothria in the intestine. 
The mouths of each of the four birds examined contained hundreds of some mal- 
lophagous parasite. These were attached to the mucous membrane by the head, and 
required a sharp pull with the forceps in order to detach them. They were attached 
in clusters, so that a dozen or more could be removed at one time with small forceps. 
They were on the inside of the pouch, near the larynx, in the larynx itself, in the 
beginning of the oesophagus, and in the buccal cavity generally. The oesophagus con- 
tained an immense number of a rather slender nematod, 10 to 15 millimeters in length ; 
these were usually attached to the mucous membrane, and left a small round hole 
when removed. In the lower part of the oesophagus and in the stomach there were 
also large numbers of nematods. These were larger than those in the oesophagus, 
with thickish, usually dark-colored, bodies; they were not attached to the mucous 
membrane, but in the stomach were in the midst of the food. 
The stomachs of each of the birds contained practically nothing but partly 
digested tish. 
Much of the stomach contents of each of these birds had suffered so little from the 
processes of digestion that the size of the fish could be easily estimated. In each case 
the fish which had constituted the last meal of these birds were from 30 to 36 centi- 
meters in length, or, in other words, the average size of the trout of the lake. There 
was a little gravel or coarse sand at the bottom of the stomach and occasionally a little 
vegetable dbbris, the feather of a small bird, etc. These apijarently had been swallowed 
incidentally to the main business of eating. These birds were found breeding on 
Molly Islands, in the southeast arm of Yellowstone Lake, July 10, 1890. 
SUPERFICIAL CHARACTERS. 
The following description of the superficial characters is based on an alcoholic 
fragment with scolex attached, and measuring about 75 centimeters. 
