444 MR. P. H. GOSSE ON THE STRUCTURE, FUNCTIONS, AND HOxMOLOGlES 
will appear by a comparison of the figures 66 and 72, while I have already proved the 
essential identity of the former with the structure in Brachlonus, See. 
118. We are now arrived at the most aberrant forms of the Rotifera, the genera 
Floscularia and Stephanoceros. In the former (figs. 79 to 82), the position of the dental 
apparatus is even more abnormal than its structure. The teeth appear to be enclosed 
in no mastax, and are placed far down in the abdominal cavity ; nearer to the cloaca, 
in fact, than to the flower-like disk. I will endeavour to explain this. 
119. The whole of the upper part of this elegant animal’s body is lined with a 
very sensitive, contractile, partially-opake membrane, which, a little below the disk, 
recedes from the walls of the body, and forms a diaphragm with a highly contractile, 
and versatile central orifice. At some distance lower down another diaphragm occurs, 
and the ample chambeV thus enclosed forms a kind of crop, or receptacle for the cap- 
tured prey. Below the second diaphragm is another capacious chamber, which we 
must consider as a stomach, since digestion evidently commences in it, and it opens 
into the intestine. 
120. The mastax, as I have above stated, is wholly wanting ; the dental apparatus, 
which is very small, evidently springing from the common paries of the stomach, 
just below the second diaphragm. That this absence of the mastax is real, and not 
illusive, is proved by the facts, that the Infusoria swallowed pass into the stomach, 
where they accumulate in its wide cavity ; that the jaws are seen to act on one and 
another, according as they come within reach ; and that, after such action, they pass 
off again into the same cavity, to undergo another mastication, when chance again 
brings them within reach of the teeth. 
121. From the ventral side of the ample crop that precedes the stomach, there 
springs, in F. ornata, a perpendicular membrane, or veil (fig. 79), extending partly 
across the cavity*. This is free, except at the vertical edge, by which it is attached 
to the side of the chamber ; and being ample, and of great delicacy, it continually 
floats and waves from side to side. At the bottom of this veil, but on the dorsal 
side, are placed the jaws, consisting of a pair of curved, unjointed, but free mallei, 
with a membranous process beneath each. 
122. Each malleus (fig. 80) is an uncus of two slender, arched, divergent fingers, 
united by a subtile web-f : the back of each curves downwards, where, expanding and 
becoming membranous, it is connected with some delicate but definite processes 
(figs. 80, 81) with rounded outlines, which I should have supposed to be muscular 
bulbs, but that they remain after treatment with potash. They are probably analo- 
gous to the loops in Limnias and Rotifer, representing the manubrium. 
* Dr. Dobie considers this waving veil, in his Floscularia cormta, to be a slit in the diaphragm, fringed with 
vihratile cilia, the motion of which, as he thinks, gives rise to the peculiar serpentine movement always observed 
at this point. (Ann. Nat. Hist. 1848.) 
M. d’Udekem describes the jaw as “ a simple plate, armed with one sole tooth.” (Bull, de I’Acad. Roy. 
de Belg. xviii. 43.) 
