Sentence:  The body was that of a well developed , somewhat debilitated white man weighing 108 lb. There were bilateral <WSD>pterygia</WSD> and arcus senilis , and the mouth was edentulous . 
Meaning of the word marked with <WSD> tags:  either of two thickened triangular layers of conjunctiva extending from the nasal edge of the eye to the cornea; it arises from irritation of the pinguecula