468 



Prof. W. K. Parker. 



[Mar. 22, 



the vertebral series is twenty in the presacral region, or only two- 

 thirds as many as in the Common Swan, eleven in the sacral region, 

 or half as many as are enclosed by the ilia, in the Swan, whose first 

 caudal corresponds with the last sacral of many birds. 



Instead of sixty-four, I can only find forty-two vertebra? deve- 

 loped in a Crow, twenty pre-sacrals, eleven sacrals, and eleven 

 candals. 



Now taking a familiar bird, the Common Chat (Pratincola rubetrd), 

 I find that it has only nineteen presacrals, eleven sacrals, and origi- 

 nally eleven candals, but only seven distinct in the adult. Now we get 

 in the cervical region in this little bird, fourteen vertebrse, one less 

 than in the Crow, little more than half as many as in the Swan, and 

 just twice as many as in the normal Mammal. 



I take np the next that comes, the Yellow Wagtail (Budytes rayi), 

 and it has the same number as the Chat ; and, indeed, in only one 

 species of Passerine bird, namely, Petroica bicolor* from Western 

 Australia, are there only sixteen free vertebras in front of the compound 

 sacrum. 



As a rule, however, in the lesser birds of this Order the number is 

 marvellously uniform, and agrees with what I have given above. 



But the lesser species of Passerines amount in number to nearly one- 

 third of the known species in the whole Class of the Carinatae. 



If it could be shown that the lesser singing birds had come up 

 directly from the low ancestral forms, they yet suggest a rather 

 long' spine for that ancestor. It might have possessed ninety vertebrae. 

 Bat I have by me most satisfactory proofs that the highest singing 

 birds came through a series of forms that are traceable towards the 

 Struthious birds, until, at last, I have no doubt of their merging'into 

 them. 



The Passerines from the Notogaea, both east and west, have among 

 them various genera that come short of the excellence of the general 

 Arctogaeal types. This is seen in the structure of their skulls, and in 

 their vocal organs, and in the lower grade of their intelligence, whilst 

 in the " Pteroptochidas," the sternum itself — a sort of anchor to the 

 classifier, which is very safe and sure in all the Passerines except 

 in two or three genera — gives way at last, and in those birds has five 

 metasternal processes instead of three. 



In the smallest of all birds — the Humming-birds — the actual number 

 of vertebrae varies very little from what is found in the lesser Pas- 

 serines, but they are generally disposed of in a different manner ; they 

 may have as many as four pairs of developed ribs in the fore part of 

 the sacrum, as in the largest kind (Patagona gigas) ; in lesser forms, as 

 Heliostrypha joarzudakii, Diplogenia hesperus, and also in the long- 



* See Owen, ' Csteol. Catal. Mus. Coll. Surg.,' vol. 1, p. 299, No. 1584. 



