Sentence:  The range is from 14 to 25 inches ; the former figure is based on a somewhat unusual birth of <WSD>four</WSD> by a Central American female ( see chapter on Laying , Brooding , Hatching , and Birth ) , the latter on a `` normal '' newly born individual . 
Meaning of the word marked with <WSD> tags:  the cardinal number that is the sum of three and one