OF THE MANDUCATORY ORGANS IN THE CLASS ROTIFERA. 
4:vj 
manubrium (c), singularly looped, but of such extreme tenuity, as to require the most 
delicate adjustment of focus to resolve it. Indeed, I have never been able to see 
more than one in a lateral view; but infer the existence of the other, from the sym- 
metrical appearance of the apparatus, in a dorsal aspect. Singular as the form of 
this organ is, I think we can recognise in it the three loops which constitute the solid 
framework of the manubrium in Euchlanis, &c. (§ 45). 
96. We have now traced the same common organs of manducation, through 
various phases, from what I ventured to call their normal development in Brachionus 
diad Euchlanis, Viewed generally, these modifications may be considered as success- 
ive degenerations of the mallei, and augmentations of the incus. I shall now return 
to the same starting-point, and trace a chain of modifications in another direction ; 
a chain of fewer links, it is true, but all tending to the same point, the degeneration 
and final obsolescence of the incus, and (in the final stage) of the mallei also. 
97. Though the types of structure, in the manducatory organs of the species which 
we have now to consider, are few, being not more than three or four, the species and 
genera are numerous ; and they may all be distinguished, by a remarkable peculiarity, 
from those with which we have been hitherto engaged. They no longer assume a 
prone position when at rest, with the venter towards the support, but take an erect 
posture, the body elevated in the same line as the foot, the tip of which is the point 
of attachment. Many of the members of one of the great groups, and all of another, 
inhabit cylindrical cases, made of gelatinous matter, thrown off from their own bodies, 
absurdly called “loricae” by Ehrenbebg, for the purpose of giving a semblance of 
unity to his artificial arrangement, but really having not the slightest analogy with the 
stiff integument oi Brachionus, Euchlanis, &c., which is an organic part of the animal. 
98. The genera Pterodina and Triarthra may seem exceptions to this generaliza- 
tion ; for the former has a distinct lorica, as has also the allied genus which I have 
Pompholyx •, and Triarthra has a posterior stylet, which, with the anterior 
pair, has been compared with the pinnse of Polyarthra ; while yet all these display 
modifications of the manducatory apparatus, belonging to the type which I am about 
to describe. 
99. I am not in this place occupied with the principles of a new arrangement of 
the Rotifera, and shall therefore merely say, that the above exceptions are apparent 
rather than actual ; though they may be considered as osculant groups. 
100. Dismissing these, I come to examine the manducatory organs as they appear 
in the genera Triarthra, Pompholyx, Pterodina, (Ecistes, Limnias, Melicerta, Cono- 
chilus, Megalotrocha , Lacinularia, and Tubicolaria. 80 far as my examinations reach 
(which include eight of these ten genera), there is no appreciable variation in the 
structure of these organs in them all ; and in one of the two, which I have never 
been so fortunate as to meet with, the deficieney has been well supplied ; since it is 
the species {Lacinularia sociaUs) which forms the subject of the admirable memoirs of 
Mr. Huxley and Dr. Leydig, already referred to (§ 6). 
