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subject, including his own examination of the teeth of 
Melicerta, he showed how all appeared to have failed in 
decyphering their anomalous appearances with perfect 
accuracy. He then directed attention to the very successful 
investigations made by the Rev. the Lord Sidney Godolphin 
Osborne, respecting the teeth of Rotifer vulgaris, and having 
not only studied with care his Lordship’s preparations, but 
also compared them with his own examinations into the 
same animal, he was prepared to endorse the chief conclu- 
sions at which his Lordship had arrived. This dental organ 
consists primarily of two slightly arcuate jaws, broad at 
their upper extremities and narrow and pointed at their 
lower ones. Elastic ligaments bind these together at each 
end. The front or convex margin of each jaw is crenulated, 
the projections corresponding with the transverse parallel 
ridges usually regarded as the teeth of the animal. These 
jaws form the two lips of a sac, the lateral parts of which 
consist of a separate tissue, which overlaps each jaw at its 
anterior margin, hooked on, as it were, to the crenulations 
and thrown by them into permanent parallel corrugations. 
Each of these corrugated organs passes first outwards and 
then downwards and backwards, where they are bound 
together by another broad membrane, which completes the 
sac posteriorly. The food enters this sac by a passage from 
the oesophagus, at its superior extremity, is crushed between 
the two jaws, and then passes out again by a similar orifice 
at its opposite or lower end to enter the stomach. Of these 
tissues the jaws are the hardest and are capable of being 
dissected out, as Lord S. G. Osborne has succeeded in doing. 
The lateral corrugated organs, have a concavo-convex form, 
