382 STRUCTUEE AND CLASSIFICATION OF BIRDS 



birds. For Parker the inclusion of Gariama in the present 

 group is impossible. Yet I find myself in this matter in 

 accord with most recent writers. If Gariama is not allied 

 to the cranes, where are we to put it ? The only alternative 

 seems to be the rails, which are in any case not far removed 

 from the present group. Mitchell has pointed but the 

 very close resemblance in the intestinal tract of cranes, rails, 

 Gariama, Otis, and (as yet unpublished) Psophia. Parker, 

 on the other hand, has emphasised the likeness between 

 Gariama and the Accipitres, a likeness which has even im- 

 pressed itself upon their external physiognomy. Forbes 

 went so far as to include in the same group with Gariama 

 the secretary bird.' It appears to me, in fact, that the 

 origin of the Accipitres is to be traced to some crane-like form, 

 and that the very varied characters of the Grues point to 

 their being a basal form connected with more groups than 

 one. As is pointed out elsewhere, unless we are to regar^ 

 the Accipitres as here treated as diphyletic, or even triphy- 

 letic, we must assume that the Cathartse and Serpentarius 

 are the most primitive forms whence the typical Falconidae 

 have been derived by a loss of two muscles of the leg. In 

 these birds the formula BXY or AXY must come before A 

 alone. But little change is required to convert Gariama into 

 Gypogeranus ; and if it be objected that this is because 

 Gariama is an accipitrine, the quite similar skull, so far as 

 the desmognathism is concerned, of Aptornis may be pointed 

 to ; it will hardly be contended that Aptornis is anything but 

 a crane or a rail. Along another line probably the peculiar 

 desmognathism of the American vultures may be derived 

 from conditions obtaining in the crane group. Parker has 

 pointed out the ossification and fusion in the middle line of 

 alinasalsin Gariama ; but in that bird the fused bones, though 

 quite analogous with, cannot be the exact homologues of, 

 the fusion of bones which has occurred in Gathartes, &c. ; 

 for the position is totally different, being much further 

 forward in Gariama. There is, however, in Psophia and in 

 others of its allies — particularly well developed in Psophia — 

 ' ' A raptorial isomorph of the Cranes ' (Parkee). 



