HYLIOTA. 
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ferent ranks, yet representing each other in then- 
own circles. An exception to this rule would seem 
to appear in Platystera , but length of hill is here 
the typical distinction of the genus: and if it is 
longer in the tenuirostral than either in the fissi- 
rostral or rasorial types of that genus, the analogy 
is still preserved ; and such, in regard to Platystera, 
is actually the case. We have thought it necessary 
to illustrate Hyliota by these varied comparisons, be- 
cause it stands at present as a single species, and 
there is consequently a want of that gradation to 
Cryptolopha which we find between such types as 
are fuller of examples. This species we shall now 
describe as the 
