Sentence:  The doctor , with the air of a man whose professional interests have found scope , drew Alex 's attention to those excellences which might otherwise have escaped him : the fine color in comb and wattles , the length and quality of neck and saddle hackles , the firm , wide spread of the toes , and a <WSD>rare</WSD> justness in the formation of the ear lappets . 
Meaning of the word marked with <WSD> tags:  not widely known; especially valued for its uncommonness