"Vol. 69.] SKELETON OF ORNJTHODESMUS LATIDENS, 393 



The Fourth Wing-Phalange. 



No trace of this wing-phalange has been found. 



The Pelvic Girdle. 



The Ischium. 



The ischium (PI. XL, fig. 6) is a deep, thin sheet of bone. 

 "The dorsal border is produced in front of the acetabulum. The 

 posterior end sends up a spur, which comprises the lower portion 

 of the posterior margin of the acetabulum. On the anterior 

 •ventral border of the plate of the ischium is a fissure determining 

 the extent of the fused pubic bone. Xo foramen is discernible. 



Prepubic Bone. 

 No prepubic bone has been discovered. 



The Femur. 



The femur (PI. XL, fig. 7) is long, straight and slender. Both 

 • extremities are robust, and the median region of the shatt is 

 attenuated. The head and neck are terminal to the shaft, and 

 the former is hemispherical. There is a large trochanter and a 

 ■ deep trochanteric fossa. 



The Tibia. 



A portion of the proximal end of the right tibia (PI. XXXVI, 

 fig. 2, ti), 115 mm. in length, is lying with its postaxial border 



- exposed, between the quadrates. The articular surface is mode- 

 rately concave, with little elevation of its margins. . The proximal 

 end is moderately robust. The postaxial surface is concave, and 

 the other surfaces are convex. The perfect bone probably almost 



-equalled the femur in length. It is hollow, but the bone is 

 thicker than the bones of the wing. Another portion of a limb- 

 bone (PI. XXXVI, fig. 2, ti), which I take to be also a part of 

 a tibia, lies across the right quadrate and the proximal ena of the 

 right tibia. If it be the distal end of the same tibia, it must have 

 been broken before petrifaction. There is no trace of a fibula. 



Summary of the Characters. 



Skull large, somewhat bird-like, cranium not arched longitu 

 •dinally, no backward projecting occipital crest, occiput concave 

 and reptilian, muzzle elongated. Length of skull = 560 mm.; 

 mandibles = 420 mm. The alveolar border ends in front of the 

 nares and 28 mm. behind the symphysis. Number of teeth, 24 in 

 the upper, and 25 in the lower jaw, all lancet-shaped, compressed 

 laterally, and interlocking. Posterior teeth larger than the anterior. 

 The last tooth of the upper jaw overlaps the lower, and the last 

 two of the lower fit into slots in the upper jaw. All the teeth 



2d2 



