287 



13S6. The iliac bones of the tamo young Ostrich. They arc longer and narrower, 

 especially posteriorly, than in other bird*. Presented by Prof. Owen, F.R.S. 



1387. The vertically and longitudinally bisected sacrum and pelvis of a young 

 Owtrich. 



It *hows the progressively incirmsing capacity of the ipinal canal and the double orifice* 

 ft* the escape of the nerves, the motor and sensitive roots of which do not unite until they 

 hare paated out. The centrum of the first sacral vertebra remain* distinct from the rcond, 

 although its neural arch and (pine have coalesced with those of the secimd vertebra and with 

 the ilia. Trace* of the articulation between the centrum of the second and third Mcral vcr- 

 tebne remain : they are obliterated in the remaining vertebnr, and the bodies of all are cellu- 

 lar and permeated by air. The (pines of 1 7 sacral vertebra; are shown in this section : they 

 are very lofty, compressed from before backwards, consist of little more than a lacework of 

 osseou* tissue, and diverge in curves from the neural arches, through the interspace between 

 the iliac bones, with both of which their margin* are confluent, and which they thus serve to 

 bind firmly together. By the peculiar cellular and pneumatic structure of the parts, not 

 more osseous texture is expended in performing the office of tie-beams across the elongated 

 roof of the pelvis than is absolutely required. * 



Pretented by Prof. Owen, F.R.S. 



1888. A vertically and longitudinally bisected sacrum and coalesced iliac bones of 

 the Diiioritia didiformu. It also shows the great expanse of the spinal canal 

 for that part of the spinal cord in connection with the nerves of the large and 

 strong hinder extremities. All traces of the original joints between the bodies 

 of the vertebra;, with the exception of the last, arc obliterated. The primi- 

 tive distinction of the neural arches is indicated by a series of elegant undu- 

 lating folds of the roof of the spinal canal : the motor and sensitive roots issue 

 separately, as in other birds. 



Prepared from a specimen presented by the Very Rev. Arckdeaco* Williams 



1339. The right femur of an Ostrich, in longitudinal section, to show its internal 

 structure. Hunti-nan. 



13UO. The right femur of an Ostrich, in longitudinal section. Hmnteria*. 



1391. The right femur of a young Ostrich. HwUeria*. 



IvS 



