736 
ON THE ENTOZOA. 
At the extremity of the head will be perceived an orbicular 
opening, which I suppose must be designated the mouth of the 
fluke. This Mr. Sowerby, however, has not been able to trace be- 
yond the representation here given of the animal, nor have I been 
more successful. It is possible that the parasite possesses the power 
of projecting this tube-like body, which now is in a state of re- 
traction. In a dried specimen it resembles a small slit. Is this 
the reason why you designate the mouth as opening laterally in- 
stead of vertically 1 It is certainly a circular opening, inclining 
somewhat to the inferior surface, both in the recent animal and in 
those preserved in spirits. Just below this is seen a small projec- 
tion. In some flukes this is very indistinct, and, at first, induced 
me to think it marked the difference of the sexes : farther investi- 
gation convinced me of my error, for it may be found in all in a 
greater or less degree of development. Sometimes it is coiled upon 
itself, and within its opening two minute globular bodies may be 
seen seemingly attached by filaments. Is this the ova-duct? 
There can be no doubt of its connexion with the ovaria ; and it 
seems to make up part of the complex genital organs which ren- 
der the animal haemaphroditic. The eggs themselves, whether 
within or without the animal, are interesting microscopic objects. 
As the latter, they may be obtained in abundance from the liver of 
a rotten sheep by diluting the bile with water, and then separating 
them by means of a filter ; there can, therefore, be no doubt of the 
truth of your statement, “ that the eggs are frequently received in 
the food. Having been discharged with the dung, they remain on 
the grass, or damp spot on which they may fall, retaining their 
vital principle for an indefinite period of time.” 
Immediately beyond this prolongation may be observed another 
opening, called by some the ventral opening, but which, in reality, 
is a sucking disc; and, consequently, some entomologists have 
given the name of distoma hepaticum to the parasite. It is com- 
