PARASITES OF ANIMALS. 69 
NEMATODES. 
Heterakis compressa Schneider. Intestine of chicken. 
HT. vesicularis Duj. Intestine of hens and turkeys. 
H. dispar Duj. Intestine of geese. 
Ascaris crassa Desl. Intestine of ducks. 
A. infleca Rud. Intestine of hens. 
A. perspicillum Rud. Intestine of turkey. 
A. maculosa Rud. Intestine of pigeon. 
Spirotera hamulosa. Gizzard of hens. 
S. uneinata Rud. Tubercles in cesophagus of geese. 
Syngamus trachealis Siebold. Windpipe, causing “ gapes.” 
Strongylus nodularis Rud. Gizzard and intestine of ducks 
and geese. 
In the preceding lists we have brought together most of the 
parasites hitherto discovered in our more common domestic 
animals. There can be no doubt but that many more will 
™ hereafter be discovered. In the rabbit, Guinea-pig, parrots, 
singing birds, and other animals often domesticated, many 
additional species occur. 
In the following pages only the more common and impor- 
tant species will be described. 
The Armed Tape-worm or Pork Tape-worm of Man (Tenia 
solium Linn.) ; andits young, the ‘ measles” of pork and hu- 
man flesh. 7 
This is perhaps the best known of all the numerous kinds of 
tape-worms. Its young or larve are common in the muscles 
and other organs of hogs, and not very rare in man. (See 
Figures 49-51.) In the adult state it is, so far as known, pe- 
culiar to the human intestine, where it is unnecessarily com- 
mon. — It grows toa great length, frequently ten to fifteen 
feet, or even more, and is then composed of upwards of 800 
joints, those that are sexually mature commencing at about the 
450th segment. The head is small, about the size of a pin- 
head, roundish, with four prominent suckers on the sides, and 
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- 
