OSTEOLOGY OF BIRDS 



187 



behind ; this is also the form of the opening on the right side in my 

 female specimen, but strange to say, on the left side of the bone 

 there,' the aperture is nearly of a circular outline. The inner mar- 

 gins of the postacetabular portions of the ilia are but placed in close 

 approximation with the corresponding borders of the sacrum, with 

 which latter they do not anchylose, while anteriorly these juxta- 

 posed margins are completely fused together. Strongest among the 

 braces afforded by the transverse processes of the vertebrae of the 

 pelvic sacrum to the ilia on either hand, are the diapophyses of the 

 first, fourth, and tenth, and these seem to be somewhat modified to 

 meet this very end [fig. 14]. Gallinaceous birds as a rule all have 

 a capacious pelvic basin, and the Jungle fowl before us affords no 

 special exception, for the concavity here is both deep and wide, 

 making ample room for the organs and viscera it protects during 

 life. 



Six vertebrae are to be found in the skeleton of the tail of G . 

 bankiva, to which is to be added a curiously formed pygostyle. 

 My male specimen has all six of these caudal vertebrae free, whereas 

 in the skeleton of the female, the anterior one has fused with the 

 ultimate urosacral. We must believe that Darwin made a slip in 

 his count, when he reckoned " seven " caudals for this form, for 

 were that so, and he seems to have included the last sacral in his 

 number, he could not but have claimed 14 for the pelvic sacrum, 

 whereas, as he rightly records, there are 15. Strictly speaking, 

 G . bankiva has four dorsolumbar vertebrae, five sacrals, and 

 six urosacrals in the sacrum of its pelvis. Even this is at variance 

 with Huxley's count, for these segments in the sacrum of a young 

 chick of the common barnyard species, where he makes but five 

 urosacrals. 1 : Nor do I believe w r e can be safely guided in this 

 matter by the " double foramina " for the exit of the spinal nerves, 

 for in the pelvis of the male bird before me, the first of these is 

 found just anterior to the transverse process of the last dorsolum- 

 bar, and counting this pair of foramina as number one, we find it 

 followed by eight other similar u double foramina" as we proceed 

 toward the urosacrals. Parker's drawing 2 seems to me to miss it 

 just in the other direction, for he gives us in the sacrum of a 

 " young fowl " but four sacrals and seven urosacrals ; this, however, 

 is much better as it makes the total count correct; and in doing so 

 sets Darwin's figures aright. 



1 Huxley, T. H. The Anatomy of Vertebrated Animals, p. 238, fig. 80, c. 



2 Parker, W. K. Birds, Encyclo. Brit., ed. 9, 3: 719, fig. 29. 



