HYLIOTA. 227 



ferent ranks, yet representing each other in their 

 own circles. An exception to this rule would seem 

 to appear in Platystera, hut length of bill 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 BOW 

 describe as the 



