THE GEELONG NATURALIST. 41 
Fasciola Hepaticum is usually found inhabiting the bile ducts of 
cep, sometimes cattle, and very rarely man. Measures about 
= Inch long, width x inch. The body is flat, ends narraw. 
Anterior or head pointed with a neck, tail not so sharp, 
(truncated). Lateral marginsuneven. Colourvaries in proportion to 
tan of bile contained.in digestive organs, brown when full, paler 
empty. 
The Fluke contains very large digestive apparatus, and is well 
provided with organs of reproduction, being hermaphrodite. It has 
been estimated that one single Fluke will produce from 10 to 40,000 
eggs. 
‘The eggs of the Fluke do not undergo any change until they are 
expelled from the host, when falling on the moist ground the embryo 
escapes and moves about with great vigour by the help of ciliaattached 
to the body, within a few days the embryo loses the power of 
locomotion due to the losing of the cilia; it then succeeds in entering 
into the body of some molluscous animal (snail) notably Planorbis 
and Bulinus or other snails found in the locality. 
(1) The embryo in its new habitat is transformed into a kind of sac 
Sporocyst or nurse known as (2) cercaria, which by a process of 
budding. reproduces a colony of redia or animaleules; these cercaria 
- pierce their way through the wall ofthe sac or sporocyst, and by means 
of a tail (much resembling the formation of a tadpole) are once more 
enabled to move through the water again, but as yet they are not 
sexually mature, only being provided with digestive and excretory 
organs, so they again enter some other mollusc by means of a boring 
process. Dr. Cobbold believes this molluse to be Lymnoeus minutus 
t loses its tail and rolls itself up in a coil and encysts itself by ` 
Secreting an earthy material. This constitutes the pupa of the liver 
Fluke. This either escapes by the death of the mollusc into the water 
or on some marshy ground where it is taken up by the sheep and once 
Barning access into the alimentary canal finds its way to the bile ducts 
ofand leading from the liver where itbecomes sexually developed, and 
in the course of a few weeks perhaps has deposited thousands of eggs 
only to undergo the various changes which its former parent has only 
recently undergone. 
Vestrus Equi or Bots. Although not coming under the class. 
Entozoa, belong tothe insect tribe; a sub-division of Arthropoda, a class 
of parasites. * 
Of all other parasites found affecting the horse’s stomach the 
larve of the vestrus equi, a member of the vestridesor gad fly family, 
is the most common. It gains access to the stomach thus— 
The fly alighting on long hair found under the chin, neck, and 
legs of the horse deposits her eggs, which, through the ageney ofa 
.glutinous material, remain in contact with the hair. After three weeks 
the eggs are hatched and bring forth a small grub or maggot, 
which, falling into the animal's food or licked off by the animal itself, 
finds its way to the animal's stomach, where with the aid of two 
hooklets they attach themselves to the mucous membrane of the 
stomach. Theirfood consists of blood which they obtain from the vessels 
circulating through the walls of the stomach, here they remain for a 
period of about8 months, when, detaching themselves from the stomach, 
are expelled by the host. They then find shelter in the. loose earth, 
