ZOOLOGY. 637 



occupy a higher rank, if in them a richness or variety 

 of forms is to be perceived. This is the case throughout 

 the Thricozoa. The Natatores, through the structure 

 and posterad insertion of their feet, through their closely- 

 set plumage, which frequently presents short and scale- 

 like feathers, by their swimming and diving, and lastly, 

 through their fish-catching, approximate as closely to the 

 structure and mode of living of Fishes as it is possible 

 for a Bird to do, while still retaining the characters of 

 its class. Many row even with the wings, and conse- 

 quently use them as veritable fins. 



Fam. 11. Reptilian Birds, Grattae or Waders. 



Legs, neck, and bill very long. 



These Birds are a lively image of, or a composition 

 from, the Reptilia, having a Frog's body with its long 

 feet, and a Serpent's neck with a Tortoise's head. 



They wade about in marshes to catch worms and 

 fish ; have also bills of very varied structure, yet gene- 

 rally very long and slender, being in some cases naked, 

 in others covered with a skin. 



Fam. 12. Typical Birds, Gallince. 



Bill and legs shorter, the former being arched, the 

 latter armed with strong toes for scraping. 



Feed usually upon grains and worms, and live in dry 

 situations. The Marsh -hens pass at once into the true 

 Fowls, and these are attached, like as is no other family, 

 through their capacity for domestication, to Man. 



Order 5. Sensorial Birds. 



3559. Run only, cannot fly. 



Fam. 13. Thricozooid Birds, Bustards. 



Fowls with long legs and mostly diminished toes- 

 Bustard, Cassowary, and Ostrich. 



These Birds have mostly such shortened wings, that 

 they cannot elevate themselves from the earth. In the 

 Cassowary we find, in place of the primary feathers upon 

 the wings, five barbless quills like so many claws. The 

 Ostrich has a pelvis closed in front like the Mammalia. 

 It has not incorrectly been compared with the Camel, 



