THE GEELONG NATURALIST. 
39 
Tape Worm {Taenia Echino coccus,), which, at one period of its life, 
inhabits the intestines of various domestic animals, notably the dog 
and sheep in this country. The segments of this worm are expelled 
from its host, and falling on the pastures, or being carried into creeks 
and dams, are eventually swallowed by sheep and cattle, and yery often 
man himself. The result is Hydatid disease. 
The eggs contained in these segments are hatched, and the young 
tape worm, or more accurately speaking, the embryo of such, is taken 
up by the blood stream, and carried all over the body, when, by a 
selective process peculiar to most worms, they escape iato the lungs 
and liver mainly, and grow into a bladder-like form commonly known 
among slaughtermen as "'water bags'* or "bladders " (Echinococcus 
Yeterinorum.) This stage of the tape worm is known as its cystic 
stage or hydatid stage. In man this cystic stage produces hydatid 
disease, only removable by operation. In sheep and cattle, etc., when 
they are slaughtered for human food, the lungs and liver constituting 
the " pluck," fall to our canine pets. The dog swallows these 
hydatids with his dish, and these bladder like bodies mature into the 
tape worm. Thus you can see how the rotation or cycle is kept 
going. If dogs and other carnivorous animals were prevented from 
devouring the viscera of sheep and cattle, and care taken to destroy 
the cysts after removal from the carcase much would be done towards 
the prevention of hydatid disease. 
The majority of tape worms, however, undergo the whole process 
of maturity in the same animal by a process of budding, i.e., each of 
the segments into which a tape worm is divided becomes in turn 
detached from the scolex or head, and is capable of developing into a 
mature worm. 
I mentioned that parasites may be of vegetable or animal origin. 
For the present we will forget all about those of a vegetable nature, 
and divide the animal class into two great sections — 
Entozoa — Those infesting the internal organs. 
Epizoa — Those dwelling on the exterior of the host, which 
include fleas, lice, bugs, and various species of Sarcopti (Mange), etc. 
The Eiiiozoa, or those which infest the internal organs, are very 
simple in their organisation. They are invertibrate, and destitute of 
articulated limbs, contain an alimentary canal, and respiration is carried 
on very feebly. These Entozoa are subdivided into three great classes 
to one of which all parasites belong, viz : — 
1. Nematoda, wliich includes all round worms. 2. Cestoday 
which includes all tape worms (flat). 3. Trematoda, fluke shaped 
worms (flat). 
My paper will consist of a few words relating to the most common 
parasites under these three heads found in our domestic animals, with 
perhaps mention of one or two existing in man, who, although termed 
lord of creation, is not too fond to act as the host to quite a number 
of parasites. 
iVema^orfa or E/Ound Worms. These as I have previously mentioned 
include all round worms, and thus make up a very large class. Most 
of them are of small size, (Pilaria, etc.,) and are generally found in 
large numbers ; are usually white, yellow, red, or marble in color. 
Male is smaller than the female, and sexes are usually separate and 
