and Classification of Birds. 259 



nection with the absence of indigenous ruminant quadrupeds); 

 wherefore the erroneous introduction of the Alectura into that 

 family, similarly negatives another fact connected with the ge- 

 ographical distribution of forms. How easy, upon this prin- 

 ciple, to affirm that the Psittacidce are represented in northern 

 Europe ! We have only to admit the crossbills into it, which 

 would be confounding groups of an inferior degree of value 

 to those which have been specified ! 



The quinary distribution of birds may, I imagine, be pre- 

 sumed to be founded on the supposition, that the rudimental 

 anatomy offers corresponding gradations to those which have 

 been indicated as obtaining externally : but, if such be the no- 

 tion, nought can be more thoroughly gratuitous, or even more 

 palpably opposed to fact. For my own part, deeming that 

 anatomy, when aided by every character which the manner 

 of propagation, the progressive changes, and other physiolo- 

 gical data supply, is the only sure basis of classification, I 

 have spared no pains to collect all the information in my pow- 

 er, that could conduce to the establishment of a permanent 

 system of Ornithology : and, by slow degrees, I have now ar- 

 rived at a general classification, most widely and essentially 

 different from that published in a late volume of 'Lardner's 

 Cabinet Cyclopaedia.' It remains to be seen which is the 

 more philosophical, or consistent with the real affinities of 

 groups. 



But little, I apprehend, can be affirmed to distinguish di- 

 chotomously the members of the insessorial sub-class, as here 

 composed. All have the toes articulated on an even plane, 

 with the claws more or less retractile : and the young are in 

 every instance hatched helpless and blind, requiring to have 

 food placed in their mouths.* Excepting in the vulture fa- 

 mily, the number of cervical vertebrae never exceeds thirteen ;f 

 and the entire vertebral formula is considerably less subject to 

 variation than in the Gressores and Natatores. These charac- 

 ters, however, are to be considered as generalizations, rather 

 than distinctions; and I am unaware of a single universal 

 character of the Insesso?°es, which will not equally apply to 

 the pigeons. It may be added, that, with the exception of a 

 very few parasitic species, which engender promiscuously^ 



* Will this apply to the Alectura P And will it not apply to the Mega- 

 podius and Menura P 



f Or rather, perhaps, to speak more strictly, twelve ; which is the lowest 

 number in this class of animals, although the* Fringillidce have been repeat- 

 edly stated to have only nine : the thirteenth vertebra bearing, in numerous 

 instances, a minute rib, which is commonly wanting in mounted skeletons, 

 having been lost in the preparation. 



y 3 



