Identifier: externalinternal00verr (find matches)
Title: The external and internal parasites of (man and) domestic animals
Year: 1870 (1870s)
Authors: Verrill, A. E. (Addison Emery), 1839-1926
Subjects: Medical parasitology Domestic animals Parasites
Publisher: (Hartford, Conn., Case, Lockwood & Brainard, printers)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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a conical, proboscis-like top, around which there are two cir-
cles of sharp hooks, 22 to 28 in each circle (Figure 53).
The neck portion is slender, crossed by fine lines, which are
wider apart as they recede from the head, finally forming dis-

70 BOARD OP AGRICULTURE.

tinct joints. These are at first very small and short, gradually
becoming broader and squarish, then oblong. The large
stare about a third of an inch in breadth and quite thin and flat
(Figure 52). The sexually mature joints or proglottides are
twice as long as broad, and contain the ovaries and a long
central egg cavity or uterus, with 7 to 12 lateral branches,
which are irregularly lobed and divided (Figure 54.) ; and also
the male organ, or testicle, in the form of branched tubes,
communicating with a penis, which is situated on one edge
of the joint, in front of the female genital orifice, and has a
curved or sickle-shaped form. The genital openings are either
on the right or left edge indifferently, in the successive joints.
Figure 49. Figure 52.
Text Appearing After Image:

The young or larval state produces the white spots known as
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Figure 49.—Pork " measles " ; natural size; Hearth and Home, after Ovv-en;
Figure 50.—Young tapeworm from measles of pork; and Fig. 51, head of same,
more enlarged; Hearth and Home, after Owen.
Figure 52.—Pork tape-worm (Taenia solium). less than natural size; Hearth and
Home, after Owen.

PARASITES OF ANIMALS. 71

, ' measles ' in pork (Figure 49). These are cavities or cysts
produced by inflammation, containing whitish fluid and enclos-
ing small, bladder-like, translucent, vesicles, filled with a watery
fluid, and which contain the proper head and neck of the young
worm coiled up spirally in the interior in an inverted position.
By gentle pressure the head and neck may be made to protrude
by inversion, like the finger of a glove, and will then present
the appearance shown in figure 50, the vesicle of fluid now
forming the flask-like caudal portion of the worm. The head
may now be seen to have four suckers and a central promi-
nence surrounded by two circles of hooks, as in the adult. In
this condition, enclosed in the cysts, they will remain living

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