The Passenger Pigeon 73 



vary in number from one to two in a set, and incubation 

 lasts from eighteen to twenty days, both sexes assisting. 

 These eggs are pure white in color, slightly glossy, and 

 usually elliptical oval in shape; some may be called 

 broad elliptical oval. 



The average measurements of twenty specimens in 

 the U. S. National Museum collection is 37.5 by 26.5 

 millimetres. The largest egg measures 39.5 by 28.5, 

 the smallest 33.5 by 26 millimetres. 



