358 



that cartilaginous or less completely ossified state which characterizes 

 the femur of a bird not quite fully arrived at maturity. The state of de- 

 velopment of the muscular ridges and tuberosities forbids the reference 

 of this femur to a very young bird, but supports the conclusion that the 

 bone had belonged to an individual as far advanced in growth as is indi- 

 cated by the difference in size between it and the femur No. 1571. 



1574. The left tarso-metatarsal bone of the Dinomis struthoid.es. It measures 



one foot in length, four inches and a quarter in circumference at the 

 middle of the shaft, and four inches across the distal end. Besides the 

 difference of proportions between the present bone and No. 1567 which 

 is indicated by these admeasurements, the anterior longitudinal concavity, 

 commencing below the rough depression, is deeper ; the channel leading 

 to the cleft between the condyles for the outer and middle toes is also 

 relatively narrower and deeper ; the posterior commencement of the 

 middle condyle projects further and more abruptly in the present bone 

 than in No. 156/ ; the posterior part of the distal half of the bone is 

 more convex. These differences, taken in connection with the greater 

 breadth and thickness of the bone, in proportion to its length, confirm 

 the conclusions of specific distinction deducible from those proportions. 



1575. The left femur of the Dinomis dromioides, Owen. This bone is of equal 



length with No. 1573, but is not so thick. The shape of the shaft of the 

 bone is also different : the relative antero-posterior diameter of No. 1573 

 is much greater than that of the present bone, especially at the proximal 

 end and trochanterial enlargement of the shaft, and just above the inner 

 condyle : the anterior surface of the proximal part of the shaft presents 

 a shallow equable concavity in No. 1575 which is not present in No. 1573. 

 In No. 1575 a pretty sharp ridge leads from the middle of the posterior 

 surface of the shaft obliquely to the upper and posterior angle of the inner 

 condyle, and the posterior surface of the expanded shaft above the con- 

 dyles is regularly excavated by a moderate concavity which is continued 

 uninterruptedly into the inter-condyloid depression. In No. 1573 an 

 oblong rough tuberosity, with its long axis parallel with that of the bone, 



