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PACHYORNIS LYDEKKER. 



THE skull is either vaulted or flattened, with a sharp and narrow beak. 

 The paroccipital processes are shorter and more rounded, and the 

 basi-occipital tubercles more prominent than in Anomalopteryx, while 

 the quadrate and mandible resemble the same bones in that genus somewhat 

 closely. The sternum is flat and very broad and short, with no coracoidal 

 facets, a very small xiphisternal notch, broad and short costal processes, and 

 widely divergent lateral processes ; while there are only two costal articulations. 

 The pelvis is extremely low and wide, with the anterior wall of the acetabulum 

 very deeply concave, the ventral surface of all the vertebrae behind the true 

 sacrals narrow and convex, and from which the very broad sacral ribs ascend 

 to join the ilium, of which the inferior postacetabular border is very sharp, 

 and descends far below the level of the ribs. There is no pectineal process to 

 the pubis. The tibio-tarsus is very short, with the shaft curved outwards, 

 the distal extremity markedly inflected, and the fibular ridge much shorter 

 than in the other genera. The fibular border below the smooth space at 

 the distal extremity of the fibular ridge is extremely rough ; and the distal 

 extensor tubercle is very prominent, being situated partly on the line of the 

 upper half of the extensor groove, instead of being altogether external to 

 the same. 



The tarso-metatarsus is still shorter and wider than in Emeus, the 

 width at the middle of the shaft being usually rather more than one third 

 of the length. The third trochlea is more prominent than in the other genera, 

 and rises very abruptly from the shaft, the outer border of the anterior surface 

 usually expanding suddenly at the proximal extremity, and the outer ridge of 

 this surface being always more prominent than the inner, whereas in the 

 other genera the opposite condition obtains. The femur, as compared with 

 that of Dinornis, is very much shorter and thicker, with a longer neck, and 

 the head rising and projecting very considerably, the linea aspera mainly 

 forming a rough nodule near the distal end of the shaft, the outer surface of 

 the distal extremity more suddenly expanded, and the popliteal depression 

 larger, more open, and leading to the inner surface of the shaft by a more 

 distinct channel. The profile of the inner condyle is wider antero-posteriorly, 

 and more rounded, the anterior intertrochlear surface being deeply channelled. 



The phalangeals of the pes are much shorter and stouter than in 

 Dinornis, the proximal surface of the terminal segments generally presenting 

 a trefoil-shaped contour. The length of the tarso-metatarsus is very much 



