ROTIFERA. 419 
ORDER I. 
ROTIFERA. 
te 
a 
The Rotifera, as above stated, are distinguished by a 
greater degree of complication. ‘Their body is oval and ge- 
latinous ; we can distinguish in it a mouth, a stomach, an in- 
testine, and an anus near the first. It most commonly terminates 
posteriorly in a tail that is variously constructed, and ante- 
riorly it bears a singular organ, variously lobate, with denti- 
culated edges, and of which the denticulations vibrate success- 
ively in such a manner as to give the organ itself the appear- 
ance of one or more dentated and revolving wheels. One or 
two prominences on the neck have even appeared to some 
observers 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(1). 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 Rotifere 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 reacquires life and motion 
on being humected with a little water. 
The Tricnocrerca, Lam., appear to me to differ from the Furcu- 
(1) For the organization of these animals, see the Memoir of M. Dutrochet, 
Ann. du Mus. XIX, p. 355. 
