250 EURYLAIMINJE. 



Rhipidura and Platystomus. In this manner we 

 might test these two circles through the whole class 

 of ornithology, and gain the same results ; for as 

 every natural group is but a representation, under 

 different modifications, of the five primary types of 

 Nature, it follows, that if they agree with one, they 

 will agree with all. In regard to the aberrant sub- 

 families, represented by the genus Quwrula, Psaris, 

 and Fluvicola, the circles, though imperfect, are 

 proved to be natural, for they have their represen- 

 tations in the two we have been comparing ; and, 

 therefore, if they belong to this family at all, and 

 this cannot admit of a doubt, they will follow 

 each other in the order we have placed them : and 

 this point, also, has been established by the preced- 

 ing analysis. Before the discovery of Platystomus, 

 the affinity of Qwru'a to the Eurylaimina might 

 have been doubtful ; but it seems to be no longer so. 

 And, setting aside all other considerations, these 

 two birds alone agree in the curved form of the 

 commissure; while the Pachyrhynchus pectoralis 

 connects Querula, on the other side, to the great 

 series of the Muscicapidce, through Psariance and 

 Fluvicolince. Future discoveries will no doubt fill 

 up the smaller links, and probably alter some of the 

 location of the types ; but, until that period arrives, 

 we know not any fact or argument sufficiently strong 

 to induce us to suspect the general principles of the 

 arrangement of the family to which this volume of 

 the NATURALIST'S LIBRARY has been devoted. 



