538 ZOOLOGY. 



in the upper Cretaceous beds of this country. The remains 

 of Ichthyornis indicate an aquatic bird about the size of a 

 pigeon. The reptilian affinities are seen in the vertebrae, 

 which, unlike those of all other birds, are biconcave, and in 

 the long, slender jaws, with stout, conical teeth held in 

 sockets, as in the crocodiles. On the other hand, the wings 

 were well developed, and the legs were of the ordinary bird 

 type, the metacarpal bones being co-ossified, while the ster- 

 num was keeled. In a second member of the group {Hes- 

 perornis) the teeth were in grooves, the vertebrae as in recent 

 birds, the sternum without a keel, and the wings were rudi- 

 mentary (Marsh). 



Sub-class 3. Ratitm. — This group, represented by the kiwi- 

 kiwi, bhe moa, cassowary, and ostrich, is characterized by 

 the smooth unkeeled sternum and the short tail ; the wings 

 are rudimentary and the hind legs strong, these birds (except 

 Apteryx) being runners, and either of large or, as in the 

 extinct forms, of colossal size. 



The sipiplest form is the " kiwi-kiwi," or Apteryx of 

 Xew Zealand (Fig. 461), of which there are three or four 

 species. It is of the size of a hen, with a long slender beak, 

 the nostrils situated at the end of the upper jaw, while the 

 body is covered with long hairy feathers. The female lays 

 only a single large egg, which weighs one quarter as much as 

 the bird itself, in a hole in the ground. It is a night bird, 

 hiding by day under trees. 



The giant, ostrich-like, extinct birds of New Zealand, 

 called moa, and represented by several species, chiefly of 

 the genera Dinornis and Palapteryx (Fig. 461), were sup- 

 posed to have been contemporaries of the Maoris or natives 

 of New Zealand. While a fourth toe {hallux) is present in 

 the Apteryx, the moa-bird has only three toes. 



The largest of. the moas, Dinornis giganteus of Owen, 

 stood nearly three metres (9^ feet) in height, the tibia or 

 shin-bone alone measuring nearly a metre (3 feet 10 inches) 

 in length. These moa birds belong to three genera : Di- 

 nornis with ten, Palapteryx with three, and Aptornis with 

 a single species. 



Allied to the moa was a still larger bird, the Mpyornis 



