ON THE ENTOZOA. 
737 
posed of strong muscular fibres, and is imperforate, or, at least, it 
has no traceable communication with the internal parts of the ani- 
mal. The question naturally arises, Does this parasite, receiving 
his aliment by one tube, after having absorbed the nutritious par- 
ticles from it, return it by the same, as do the polypi, and other 
animals even still lower in the scale of organization, even the 
monads ] 
The singularly constructed eyes of which you speak, I have not 
been fortunate enough to perceive, nor has Mr. Sowerby, nor some 
other friends. This shall be the subject of a future inquiry, when- 
ever I am again in possession of the living fluke. 
I am sure you will pardon the freedom with which I have writ- 
ten, for I know your love of every thing which advances veterinary 
science. 
Mr. Bracy Clark, when describing the tricocephalus equi, 
asks if the smaller end is the head or the tail. Writers on ento- 
mology state it to be the former, and hence the name they have 
given to this worm. I feel, however, convinced that this is a 
mistake. Having examined several, I cannot discover the least 
resemblance to a head at the extreme termination of the tapering 
portion of the worm ; but at its obtuse end a prolongation is per- 
ceptible, similar to the head of the tcenia. Whether, like the last 
named parasite, the tricocephalus possesses the power of projecting 
and again retracting its head, I do not know. 
It would be an interesting employment, and not altogether a 
profitless one, for some of the members of the profession who have 
made natural history their study, to give us a classification of 
these parasites. I beg leave to subjoin a table which I have been 
in the habit of using when referring the student to the medicinal 
substances which are resorted to in order to get rid of these tor- 
mentors. I know that it does not contain all that it ought, nor, 
perhaps, is it so scientifically arranged as it might be : it may, 
however, prove a provocative to others to give us something 
better. 
Parasites infesting Domesticated Animals. 
ENTOZOA. 
CEstrus — The Bot. 
•CEstrus Equi 
HiEMORRHOIDALIS 
— Veterinus 
— Bovis 
The spotted-wingedhorsebot 
The fundament bot 
The red bot 
The ox bot 
Ovis 
The sheep bot 
j Found in the stomach 
Found under the skin of 
the back 
Found in the maxillary 
sinuses. 
5 D 
VOL. XII. 
