326 



ELEMENTARY ZOOLOGY. 



earth, as in the case of the ostrich, to very carefully 

 made swinging baskets, such as those made by the oriole, 

 the tomtit, or the tailor bird. 



The young in such forms as the chicken or the quail 

 are well developed when they hatch. Very soon they are 

 able to run about and seek their own food (precocial 

 young). In the case of the pigeon or the blue- jay, the 

 young are poorly clothed and are helpless for a much 

 longer period (altricial young). The higher forms are 

 the longer dependent. (See Fig! 132.) 



FIG. 133. Archceopteryx lithographica, an early reptilian bird. From Claus. 



Questions on the Figure. What in the figure shows it to be a 

 bird? What shows it to be different from typical birds? What is 

 signified by each of the terms in its scientific name? 



331. The Principal Orders of Birds. The sub-divisions 

 of this class do not mean as much as in the other classes 

 of vertebrates. The birds are more alike, and the 

 divisions are based on activities and superficial structures. 

 There are sixteen or seventeen orders of which the student 

 may likely see representatives. For fuller description 

 of these orders the student should refer to more extended 



