THE FLEXIBLE CREEPERS. 
483 
the name of science. But these also must be modified a little. 
The prongs must be bent abruptly at about a right angle to 
the handle, where, however, a hinge-joint must be made, so as 
to allow this angle to be considerably varied. Now take these 
modified forks, and set them up one on each side of the blades 
of the shears, handles downward, at such a distance that the 
prongs shall just rest on each blade. These are the upper 
jaws, technically mallei, the prong part being the uncus of each, 
the handle the manubrium. 
So we have the solid parts of this remarkable mouth. The 
prongs are fixed to the blades by elastic ligaments, so 
that when the former are drawn back the latter are stretched 
open, though both the blades and the forks have proper and 
independent movements, effected by means of muscles. The 
whole is contained in a three-lobed mastax, which does not 
importantly differ from that before described ; and you may 
again have recourse to the parchment-covered cylinder of 
glass, to imagine the situation of the whole affair within the 
transparent body of the animal. 
I have intimated that there is considerable modification in 
detail in these parts as found in different species. I have had 
specially in view Notommata aurita in my illustrative com- 
parisons. In Eosphora, however, the blades are more pincer- 
like, coming together only at their tips, and the forks are but 
two-toothed, one tooth being more prominent than the other, 
and projecting over the blades, so as to cross with the tooth of 
the opposite jaw. In this, and in several other species, the 
mastax can be brought to the front of the face, so that the 
points both of the upper and lower jaws protrude ; when so 
placed the animal frequently snaps them fiercely, and their 
close analogy with the two pairs of jaws in a carnivorous 
beetle becomes very evident ; an analogy which, if we saw 
them only as they occur in many kinds of Rotifera, perma- 
nently inclosed far within the cavity of the chest, we could 
scarcely have imagined. It was this and similar observations 
which first compelled me to identify what has been commonly 
miscalled the “ gizzard” in the Rotifera with the mouth 
and horny jaws of Insects. 
The protrusion and snapping action of these two pairs of 
jaws are very strikingly exhibited by an attractive and beau- 
tiful race, the animals of the genus Synchceta. These are 
mostly found in large collections of clear water, such as lakes 
and ponds and reservoirs ; rarely or never in those minute 
stagnant pools and ditches in which many Rotifera delight. 
They appear to require a wide area in which to expatiate, and 
the element must be of the purest, or it will not do for 
Synchceta. In such collections of water animal life is usually 
VOL. II. — NO. VIII. 2 L 
