57 



an author's constructiou is a cheap way of gaining notoriety ; but to 

 show what should have been done originally, and to rexjlace the 

 damaged " brick " by a sound one, 



" Hoc opus, liic labor est." 



In Plate IX. I venture to put forward an arrangement of the Class 

 '' Aves " framed on a somewhat different idea from those of my pre- 

 decessors; and it will be observed that I have not attempted an 

 arrangement under the headings of Subclasses or Orders^ with their 

 accompanying minor groups. Here are merely the birds which now exist, 

 with some of their allies which have perished ; and the groups which are 

 un-named ia my map of the Class will be found later on {infra, pp. 67- 

 88), where I have re-drawn my scheme (PI. XII.), taking into account 

 the classifications of Flirbringer and Seebohm. 



From the map (Plate IX.) which is here presented I have drawn up a 

 phylogenetic scheme (Plate X.) to test the correctness or incorrectness 

 of my views ; and it will be seen that I have not treated my subject quite 

 on the same lines as those pursued by Reichenow and Fiirbringer. For 

 this reason : by the model of the '' tree " which is on the table, we see 

 that Fiirbringer, and before him Reichenow, adopted the figurative notion 

 of a tree literally ; and this plan, excellent in every other respect, seems 

 to me to fail in one particular, in that it subordinates the fact of the 

 persistence of certain types to the present day. Such types may be of 

 ancient differentiation — that no one may question ; but the fact remains 

 that they exist in our own Epoch. 



Thus, if it were possible, Ave should stand at the foot of the Avian 

 tree — or, to speak more correctly, of the main Avian branch of the 

 tree when the Birds had split off from the Reptiles. We could look 

 up into the many spreading branches and twigs of '' Aves," could 

 note those which had died out or were expiring, and nowhere should we 

 get this allegory more completely fulfilled than in the pictures of 

 Fiirbringer. 



But the ornithological tree is a different one from a natural tree. It 

 is one in which all the surviving branches have reached the same 

 level, and the only difi'erence in their appearance, as avc see them on the 

 topmost horizon, is that whereas one bough has struggled to the top, 

 and many of its branches have died off in the process, another bough 

 comes to the summit of the tree full of smaller branches and flourishing 

 twigs. 



Thus we ought, if we wish to arrive at a knowledge of the present 

 state of our ornithological tree, after standing at its base and studying 

 the development of its many branches in different directions, to take a 

 flight in an imaginary balloon, from which to look down upon the 

 summit of the tree, so as to see what branches have attained to the top. 

 The result would, I hope, be something like the map which I place before 



