AVES. 

 FIG. 210. 



49 



FIG. 210. Ross' Gull (Rhodostethia rosea). Upper figure adult male; lower, young 

 female. From " Chapters on Natural History " ; drawn by Dr. R. W. Shufeldt after 

 Ridgway. 



Questions on the figure. What indications of structural adaptation 

 to habits do you find in the figure ? What sexual dimorphism is per- 

 ceptible? 



are laid in holes in the sand. Ostrich culture is an important 

 industry in South Africa and to a certain extent in America, 

 on account of the plumes which are extensively used as orna- 

 ments. Besides the types mentioned there are a number of 

 extinct forms belonging to this division, some of which have 

 become extinct in recent time. ZEpyornis is one of these, 

 formerly a native of Madagascar, where remnants of its eggs 

 have been discovered showing that its volume was about six 

 times that of the ostrich egg, i. e., having a capacity of about 

 two gallons. 



