202 PROCEEDINGS OF THE ACADEMY OF 



of Insessores to hop. Pigeons are cursorial iu that they (invariably I believe) 

 walk : and other rasorial features need not be dwelt upon. They are also 

 schizognathous, like Rasores. On the other hand, it is a fundamental character- 

 istic of 'Cursored to have the hallux elevated, though Herodiones are a single 

 exception. This feature is not presented by the pigeons, which are moreover 

 mostly as truly arboricole as the majority of Tnsessores. They are mostly Al- 

 trices, like the last. The balance appears in favor of their being Tnsessores, as 

 the author holds them. 



The Ostriches and affines are in this arrangement reduced to an order 

 Brevipennes of Cursores. Archseopteryx is not noticed, as may be said of other 

 extinct forms. 



Twelve orders succeed to the three sub-classes ; agreeing in the main with 

 divisions almost universally recognized, and defined iu an unusually satisfac- 

 tory manner. A notable point of difference between this and other systems 

 lies in the tenth order, Strisores, which, as framed, does not largely accord 

 with any previously established group. It is " a polymorphic group." as the 

 author says, not easy to define by positive characters An order Zygodactyli, 

 equivalent to Scansores auct. is retained ; here, if anywhere, ulterior revision 

 and decided modifications may be required. The zygodactyle birds appear to 

 have so long had their place as a distinct order more because it has not been 

 clear what to do with them" if dismembered, than anything else. Toes iu pairs 

 is a thoroughlj^artiticial character, as used; it is universally allowed that it 

 unites birds otherwise widely dissimilar. It seems to be really only a modifi- 

 cation to which any one family or genus of several groups is liable ; if so 

 its value has been largely overrated. It is most probable that the "order"' 

 Scansores or Zygodachjli will be broken up, in time, or at least restricted to 

 some one of the types — perhaps the parrots, — now included under it; more 

 fitting places being found for the cuckoos, trogans, toucans, woodpeckers, &c. 



Regarding Prof, Lilljeborg's Natatores, I may express my conviction that 

 the four orders he defines are the only natural ones, and that as such they 

 must ultimately prevail. 1 only criticise the division of these four orders 

 into two "groups;" an intercalation between the subclass and the orders 

 that is at least superfluous. Not that all the distinctions implied in the 

 terms " Simplicirostres" and '^ LameUirostres " do not obtain ; but that the 

 groups are inequivalent. Lamelliroslres are not more different from the Sim- 

 plicirostres than the several components of the latter are from each other. 

 A goose, e. g., is not more different from a gannet than a penguin is. On 

 this ground I hold the division to be unnatural as well as unnecessary. The 

 two groups are further redundant, in that they have no analogues in other 

 parts of Prof. Lilljeborg's admirable system.* 



With the foregoing qualificaiions I follow this arrangement very closely. 

 But I think that ornithologists will find it necessary to adopt many more 

 families and sub-families than this author does, particularly among higher 

 groups. I find it so even among Natatores, as will appear in the sequel. 



NATATORES. 



Relations and analogies of the sub-class. 

 Swiming-birds are so definitely circumscribed, that there appear to be but 

 two types liolding disputable place. Phoenicopteridie have just been noticed. 

 Helio'rnithidw. have been located with the Grebes, by Schlegel and others, ap- 

 parently on account of the lobed feet. But this is surely an error ; the rela- 

 tionship is of analogy, not affinity. They have been referred to Steganopodes, 

 next to Flofidsc, by Bonaparte and others; upon what ground does not 

 appear. As already said, osteology carries them to fulicarious Grallx. It 



* I doubt, too, that the definitions of these groups will .«tand test without qualification. 

 In general, as claimed, one is altricial, the other prrecocial ; but among Pygopmles are 

 instiinfcs of botli. Lamellation of the bill is a very general distinction ; but Prion. 

 among " Simplieirostres " has laminte. 



[Dec. 



