THE ROTIFERA. 293 
digestive apparatus is by no means simple; the stomach is long, 
and has on each side lateral appendages, terminating in a great 
intestine. The heart of the rotifers is in constant action, and 
its pulsations are quite discernible. We cannot conceive such an 
organ unless it be connected with a system of circulation, but this 
we have not been able, as yet, to decipher. It used to be the opinion 
that minute creatures had always a very simple organisation, but 
the revelations of the microscope have caused naturalists materially 
to alter their views upon this point. Minuteness does not elude 
that perfection which the touches of the great Creator’s hand 
stamp upon his work. The wheel-bearing animalcules have 
generally a single eye fixed in the cyclopean position; and, like 
all the eyes of the minute creation, it is red. Some of them have 
more than one; even rotifers with four eyes are known. The 
eye is sometimes placed upon the neck or on the back, so that 
the animal can only see above it and behind it, but not below 
it or in advance. We do not know the exact reason of this 
position ; but the animal is so lively that it can matter little where 
the eye is situated. And, moreover, the rotifers have a peculiar 
power of retreating, not into their shells, for they have none, but 
into their skins, and in this form they appear like a ball. The eye 
may be placed with regard to this position, so that the retired 
creature may keep a sharp look out. 
Ehrenberg declares that he finds indications of the existence of 
a nervous system. It requires a stretch of imagination to follow 
the celebrated naturalist, even to conceive a network of nerves in 
an animal which a grain of sand could effectually bury. Like 
most of the crustaceans, the rotifers are oviparous, carrying their 
eggs suspended at the root of their tails. 
Spallanzani has brought the wheel-bearers into great repute 
by proving that they are endowed with a wonderful power of life. 
He found that they could be dried and folded between the leaves 
of a book, and kept in this unnatural state for even two years. 
They seem to be in a state of lethargy, and in apparent death ; 
but when again immersed in water they revive, and seem none the 
worse for the intermission in their vitality. Many of the eminent 
naturalists of the day refused to believe anything so extraordinary. 
