UIBOTIIRIA FROM YELLOWSTONE NATIONAL PARK. 
67 
may be regarded, however, as the first indications of the strobile condition, in which 
the segments are bnt little individualized. Usually there are a few lateral longitud- 
inal striie, and invariably a rather strongly marked median furrow, which begins 
a short distance behind the anterior end and extends almost to the posterior end, 
becoming more evident in the median and postero-median regions of the body. When 
magnified a few diameters this median line appears to be made up of a row of punc- 
tate depressions, very near together, but approximating a zigzag line, indicating 
what is shown more plainly, in sections, that the reproductive openings are arranged, 
in the adult, along the median lateral line. 
The largest specimen measui’ed 28.5 centimeters in length. At the anterior end 
it was 8 millimeters broad; 7 millimeters back of the anterior end the breadth was 
11 millimeters ; near the anterior end the breadth was 1.5 millimeters. The thickness 
throughout was about 2 millimeters. 
Another specimen had the following dimensions : Length, 19.3 centimeters ; diam- 
eter of compressed head, 2.5 millimeters; breadth near anterior end, 6 millimeters; 
greatest breadth, 70 millimeters from the anterior end, 9.5 millimeters; breadth near- 
posterior end, 2 millimeters, tapering thence to a point ; thickness about 2 millimeters. 
Three specimens from a single host were 120, 110, and 106 millimeters in length, 
respectively. The breadth near the anterior end of each was 4 millimeters ; the 
greatest breadth of No. 1 and No. 2 was 8 millimeters; of No. 3, 0 millimeters; the 
breadth of each near the posterior end was 1.5 millimeters. In No. 1 the greatest 
breadth was about 27 millimeters from the anterior end; in Nos. 2 and 3 it was about 
15 millimeters from the anterior end. 
The specimen mentioned above which measured 19.5 centimeters in length came 
from a fish which measured 11 centimeters in length, exclusive of the tail-fin. Since 
it was not possible to straighten the worm without breaking it, and since the alcohol 
had doubtless caused it to contract more or less, the length obtained by measuring the 
alcoholic specimen is certainly less than that of the living specimen. The weight of 
the host was in this instance 20.7 grams ; the weight of the parasite was 2. 65 grams, 
or about 12;| per cent, of that of the host. 
In a small sucker, 9.5 centimeters in length, exclusive of the caudal fin, three para- 
sites were found, the measurements of which are given above. The weight of the 
host was 9.1 grams, while the combined weight of the three parasites was 2.5 grams, 
or nearly 27J per cent, of the weight of the host. Or, to make a parallel case, in order 
to infest a man weighing 180 pounds to an equal degree it would require nearly 60 
pounds of tape worm. 
Among the specimens which had been separated from their resiiective hosts before 
coming into my possession I find one that is quite different in shape from the others. 
It is 40.5 millimeters long and 10.5 millimeters broad and terminates bluntly at each 
end. It is probably the anterior end of a large specimen which has been broken 
while living so as to allow the muscles to contract strongly and obscure the broken 
part. 
Anatomy . — On account of the few external characters of which use can be made 
in the identification of these specimens, it became necessar}' to make some investiga- 
tion into the histological structure. In these investigations portions were stained with 
harmatoxylon, borax carmine, Bismark brown, etc. The most uniformly satisfactory 
results were obtained with borax carmine, Grenacher’s formula, 35 per cent, alcohol. 
