126 PKOFESSOE OWEN ON THE GENUS DINOENIS. 



q. Obturator notch. r. Pelvic disk. 



s. Sacral vertebrae (s i, in PI. XV. fig. 2, marking the anterior articular surface of the 



first centrum). 

 t. Interacetabular cavity. u. Postrenal cavity. 



V. Hio-ischial plate or deck-like production. 



2. Prezygapophysis (marking, in PI. XIV. fig. 1, that of the first sacral vertebra). 

 1-20 indicate the sacral vertebrse from before backward. 

 62. Ilium. 63. Ischium. 64. Pubis. 



In the restoration of the skeleton (in which I have taken the vertebral formula of 

 Ocydromus) the Aptornis defossor, with the neck bent and head supported as in the 

 ordinary standing position of the bird, would be about 3 feet in a straight line from 

 the top of the head to the soles of the feet ; the length, in a straight line, from the 

 end of the beak to that of the tail would be about 2 feet 10 inches. The chief depar- 

 ture from the ordinary form of the Coots is seen in the shorter and more robust 

 proportions of the tibiae and metatarsal segments of the legs, in which feature Notornis, 

 amongst recent Eallines, offers the nearest approach to Aptornis. 



DESCRIPTION OF THE PLATES. 



PLATE XIV. 



Fig. 1. Side view of pelvis of Aptornis defossor, nat. size. 

 Fig. 2. Front or under view of sternum of ditto, nat. size. 

 Fig. 3. Back or upper view of sternum of ditto, nat. size. 

 Fig. 4. Side view of sternum of ditto, nat. size. 



PLATE XV. 



Fig. 1. Upper view of pehds of Aptornis defossor, nat. size. 

 Fig. 2. Under view of pelvis of ditto, nat. size. 



PLATE XVI. 



Fig. 1. Kestoration of skeleton of Aptornis defossor. \t\i nat. size. 

 Fig. 2. Skeleton of Ocydromus australis, \t\i nat, size, 



