346 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
millimeter iu length aud 1 millimeter in breadth. The terminal segments in this frag- I 
ment are 2.75 millimeters broad and 1.25 millimeters iu length. 
This fragment, for the most part, resembles the larger specimen, being flattish, 
white, roughened by transverse wrinkles, aud having its margins at one part of its 
course ruffled. In one place, however, 7 centimeters from the head, aud for a distance || 
of 3 centimeters, it is shrunken, attenuated, and yellowish. A segment in this part 
measured 1.5 millimeters in length aud barely 1 millimeter iu breadth. Immediately j 
beyond this the normal segments wei’e 5.75 millimeters in length aud 2.5 millimeters ! 
in breadth. | 
Some slender, attenuate fragments, previously alluded to, looking when first col- i 
lected like tangles of narrow braid, were at first supposed to be a distinct parasite, i j 
Subsequent examination demonstrated them to be fragments of mature portions of the ; i 
large DibotUrium. Following is a more detailed account of these fragments than has ' 
yet been given : One fragment, measuring 34 centimeters in length, was very thin, and 
about 1.5 millimeters broad. In some places segments could be made out. These , 
were much attenuated. Some of them were measured and found to be 3 millimeters 
in length. In some shorter fragments, which were quite irregular, being flat in places 
aud in others cylindrical, segments were noticed which were 4 millimeters in length 
and 1.25 millimeters broad. Another fragment, 33 centimeters in length, was reduced 
throughout the greater part of its length to a mere filament one- fourth of a millimeter || 
or less in diameter. Another fragment, about 30 centimeters in length, was reduced l! 
to less than one-half of a millimeter in diameter throughout most of its extent, but jj 
widened iu each direction, so that each extremity was a little over 1 millimeter iu |j 
breadth. 
A thin fragment was placed in glycerine, and was then seen to contain ova along || 
its entire extent. The ova lay along the median line in clusters, which were somewhat || 
continuous. In this the jointing was indistinct. In some of these fragments the joints || 
are distinct, although there is no tendency in the joints to separate. A fragment, 
35 centimeters in length, showed distinct joints in part of its course ; in other places b 
the joints were indistinct. This fragment was flat aud thin aud about 1.5 millimeters 
wide where it was flattened •, in other places it was not quite so wide, owing to a tend- ,] 
ency to roll up at the margins. Both the flattened portions and the attenuated, p 
cord-like portions of these fragments were found to contain ova, which were seen to |j 
be abundant in specimens made transparent iu glycerine. These slender fragments |] 
are evidently portions of the larger strobiles, iu which the muscular tissue has degen- -J 
erated, aud the whole structure is reduced to a narrow baud of connective tissue con- Ij 
taining ova. il 
ANATOMY. ii 
\ 
In order to make a comparison of the structure of the adult with that of the i 
larva, portions were stained with borax carmine and cut into thin sections. These | 
were made in three directions, transverse, longitudinal parallel to the margin, and 1 
longitudinal parallel to the lateral face. | 
Sections of the head show that while that organ is somewhat smaller than it is in \ 
the larger larvae, the muscular fibers are much more abundant aud more strongly p 
developed (Fig. 34). In outline and arrangement of parts they are the same. There 
appear to be three principal systems of muscles or contractile fibers in the head, 
