Mr. A. R. Wallace on the Natural Arrangement of Birds. 199 



connects them ? The Swallows appear to us to be farthest 

 removed from any of the birds hitherto placed in the tribe. 

 Their small size, powerful flight, and com})act plumage, added 

 to their strongly grasping feet, seem to shut out any direct 

 affinity with them. It is, then, in the Caprimulgidte that we 

 must look to discover the affinity we are in search of; and we 

 believe that the only group to which we can approach them is 

 the Trogonida. The average size, the excessively thin skin, the 

 mass of downy plumage, the general form, the nature of the 

 food, and, in many species, the mode of capture, all ])oint to an 

 affinity in this direction. The different structure of the feet is 

 the most important character on the opposite side of the question ; 

 but as this equally exists in such an undeniably closely allied 

 family as the Priunitidce, it need not be considered an insur- 

 mountable obstacle. There is, no doubt, still a very wide chasm 

 to be passed over ; but it will be still w ider if wx compare them 

 with any other family of the Fissirostres, with which their ana- 

 tomical structure, as well as the general considerations before 

 alluded to, compel us to place them. AYe consider, then, the 

 Swallows and Goatsuckers to exhibit the greatest development 

 of the Fissirostral form ; or, if the term is preferred, to be the 

 typical groups. And, as a consequence of this position, they 

 can neither of them serve as the connecting links or transition 

 to any other tribe or order of birds ; for if the Fissirostral 

 character is what serves to distinguish this tribe from all others, 

 it must certainly follow that those birds which have this cha- 

 racter in its highest develoj)ment must be most distinctly sepa- 

 rated from all the species of any other gi'oup. We have here 

 another reason for believing that the resemblance of the Goat- 

 suckers to the Owls is one of externals, and not of essentials, — 

 of analogy, but not of affinity. 



We have now briefly })assed in review all the families w-hich 

 possess the characters of Fissirostral birds in a plain and obvious 

 degree, and w hich, without the greatest violation of their natural 

 affinities, cannot be placed elsewhere in the system ; but there 

 are several others which have been associated with these by many 

 naturalists, some of them we believe erroneously. And, first, 

 the EurylaimidcE, or Broadbills of the Eastern Archipelago, have 

 been, and still are, generally placed among the Fissirostres. 

 They have, however, in our opinion, no right whatever to this 

 situation, being true I'assercs, allied to the Culingas and Querulas 

 of S. America. The Eurylaimus Juvanicus and the Cynibirhijnchus 

 macrorliijnchus feed in the same manner as ordinary perching 

 birds, ho])piug about the branches of trees, and picking off the 

 fruit, which forms their principal subsistence. Their legs are of a 

 moderate length, their toes strong, and the hind toe large and 

 powerful, ichich is never the case in true Fissirostres. It is this 



