Parasites: A Treatise on the Entozoa of Man and Animals: Including Some Account of the EctozoaCobbold, T. Spencer (Thomas Spencer)
Science
Parasites: A Treatise on the Entozoa of Man and Animals: Including Some Account of the Ectozoa
Cobbold, T. Spencer (Thomas Spencer)
Helminths; Parasites
Unlike the ordinary tapeworms, the segments of the broad tapeworm do
not individually separate so as to become independent organisms, a
circumstance which is highly favorable to the bearer. Its remarkable
breadth, and the extremely numerous and closely-packed proglottides,
impart a sufficiently distinctive character; but this parasite may
be more fully characterised as the largest human cestode at present
known, attaining a length of more than twenty-five feet, and sometimes
measuring nearly an inch in breadth; the so-called head 1/25″ in width,
bluntly pointed at the tip, much elongated or club-shaped, slightly
flattened from behind forwards, and furnished with two laterally
disposed slit-like fossæ or grooves, but destitute of any armature:
anterior or sexually-immature segments of the body extremely narrow,
enlarging in a very gradual manner from above downwards; joints of the
lower half of the body gradually decreasing in width, but enlarging in
depth; sexually-mature segments usually about 1/8 of an inch in depth,
but those near the caudal extremity frequently 1/4″, and quadrate in
form; body flattened, but not so uniformly as obtains in the ordinary
tapeworms, being rather thicker near the central line; total number
of joints estimated at nearly 4000, the first sexually-mature ones
being somewhere about the six hundredth from the head; reproductive
orifices at the central line, towards the upper part of the segment at
the ventral aspect, the vaginal aperture being immediately below the
male outlet, and both openings surrounded by papillæform eminences;
uterus consisting of a single tube, often seen regularly folded upon
itself, forming an opaque, conspicuous, centrally-situated rosette; eggs
oval, measuring 1/350″ in length by 1/550″ in breadth, having three
shell-coverings, and a lid-like operculum at one end, as occurs in the
fluke-worms. Owing to the dark color of the egg shells, the uterine
rosette is readily seen by the naked eye as a conspicuous deep brown
spot at the centre of each successive segment.
[Illustration: FIG. 25.--Head and neck of _Bothriocephalus latus_. _a_,
Front view. The smaller figure represents the head as seen from the
side. After Knoch.]
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account