DURING THE PROCESS OF DIGESTION. 
159 
First Species. — Form long and flat; body provided with a granular carapace, 
convex above, flattened beneath, and indented towards its posterior part ; 
head distinct ; a band of vibratile cilia around the middle of the body; a long 
conical and moveable tail ; movements of the cilia are rapid, those of the 
body are slow ; length ^th, and diameter ^th °f an English inch. This 
animalcule bears no analogy to those already known. 
Second Species. — Ovoid form ; body covered with a carapace indented be- 
fore and behind; a conical tail; a crown of vibratile cilia at the anterior part 
of the body ; movements very distinct ; length ^ 5 th, diameter of an Eng- 
lish inch. This species is analogous to the brachionus polyacanthus of 
Ehrenberg. 
Third Species. — Form lengthened and cylindrical; a smooth carapace ; no 
tail ; vibratile cilia around the mouth ; movements very rapid ; length 7 § 0 th, 
diameter n l 5T5 th of an English inch. This species has a close resemblance to 
the enchelis nehulosus of Ehrenberg. 
Fourth Species. — Form oval; no carapace; cilia upon all the surfaces of 
the body ; buccal opening at one of the extremities ; movements rotatory 
and very rapid ; length q ? th, diameter ^th of an inch. This species bears a 
great analogy to the leucophris anodontce of Ehrenberg, and which Muller 
has seen in the water of the sea muscle. 
The carapace, or transparent envelop of these animalculse, per- 
mits the observation in their interior of the alimentary molecules 
with which they are nourished, and which render them more or 
less opaque. The number of these animalcules is so considerable, 
that in little less than a grain of alimentary matters taken in the 
first two stomachs of the sheep, there existed from fifteen to twenty 
of different kinds and sizes. 
Considering that all these animalcules are principally composed 
of fibrine and albumen, we may estimate that the weight of from 
fifteen to twenty of these animals, existing in each grain of the 
liquid of the stomach, constitutes nearly one-fifth part of the total 
weight of the liquid in which they live. Now sheep have an 
average of from 6^ lbs. to 11 lbs. avoirdupois of aliments in the 
first and second stomachs, after an ordinary repast ; the total 
weight of animals contained in these two stomachs will be the fifth 
part, or from 19 to 32 ounces. In the third, and particularly in the 
fourth stomach, these animalculse are dead, and can be recog- 
nized only by the form of their carapace, which is then transparent. 
In the small and large intestines the remains of the carapace will 
only be found. 
2 d. The horse has, in the caecum and dilated portion of the 
colon, seven species of animalculae : — 
First Species. — Form elongated, and conical at its anterior part ; head not 
very distinct ; posterior part of the body terminates abruptly ; no tail ; a 
granular carapace ; two short anterior extremities, which are articulated and 
mobile, and terminated by some strong filaments ; movements slow and ana- 
logous to those of the tortoise ; length ^th, diameter ^th of an inch. 
