452 INFUSORIA. 
the first. It most commonly terminates posteriorly in a tail that is 
variously constructed, and anteriorly it bears a singular organ, va- 
riously lobate, with denticulated edges, and of which the denticula- 
tions vibrate successively in such a manner as to give the organ itself 
the appearance of one or more dentated and revolving wheels. One 
or two prominences on the neck have even appeared to some ob- 
servers to be furnished with eyes. This revolving organ does not 
serve to direct their aliment to the mouth; it may be supposed to 
have some connection with the function of respiration *. In 
Furcutaria, Lam., 
The body is unarmed; the tail is composed of articulations which 
enter one into the other , and is terminated by two threads. 
It is on one of these—the Furcularia or “Rolifere des toits—that 
Spallanzani performed his famous experiments. Covered with dust 
in the spouts on the roofs of houses, it becomes desiccated, and after 
remaining in that state for several weeks re-acquires life and motion 
on being humected with a little water. 
The Tricnocerc®, Lam.,appear to me to differ from the Fureu- 
laria only in the diminished development of their vibratile organs f. 
The 
Vacinicoua, Lam., 
Seem to be Trichocercee with a diaphanous envelope; but we may 
be allowed to fear there has been some optical illusion f. 
TupicoLaria, Lam. 
The Tubicolarice only differ from the Furcularie, by secreting them- 
selves in little tubes, which they construct of foreign molecules, but 
which do not form any portion of their body, lke those of the Coral- 
liferi (polypiers). Their rotatory organ however shows itself out of 
the tube, nearly in the manner of the head of Polypi. 
There is a species in France common on the Conferve of the 
marshes—Vorticella tetrapetala, Blumenb.; Dutrochet, Ann. 
du Mus., XIX, xviii, 1—10—whose rotatory organ is divided 
into four lobes. 
Bracuionus, Mull. 
The Brachioni, with rotatory organs and a tail nearly similar to 
those of the Furculariz, have a sort of membranous or squamous 
shield, which covers their back like that cf certain Monoculi. 
* For the organization of these animals, see the Memoir of M. Dutrochet, Ann. 
du Mus. XIX, p. 355. 
+ Trichoda pacvillum, Mill... XXIX, 9—12; Encye., XV, 19, 20 ;—Trich longi- 
cauda, Mill., XX XI, 10. 
% Trich. innate ;—Tr. ingenita;—Tr. inquilina, Mill. 
