PI/ATE i 
At right and left, dorsal and lateral views of the head of Necator americanus free-lh ing 
larvae when full grown; between them the front view of the head and an optical section 
near the line A A; ppl, one of the four labial submedian papillae; on,onchium or pharynx; 
oe, oseophagus; glsal dsl, dorsal oesophageal gland; chrddsl, dorsal chord; amph, amphid; 
amp, ampulla of the dorsal oesophageal gland; ph, pharynx; os gl, dorsal oesopha¬ 
geal gland emptying into the lumen of the oesophagus or pharynx; msc?, contractile 
fibers(?); dir on, guiding ring encircling the anterior portion of the pharynx; trm 
amph, terminals in the amphid, presumably the end elements of nerve fibers; sal, 
dorsal oesophageal gland; nrv , and opposite A A, nerve passing to one of the submedian 
labial papillae; lum oe, lumen of the oesophagus. The dorsal and lateral sketches were 
made from living specimens, the front view and section from specimens fixed in 
Flemming’s solution and mounted in glycerin jelly. 
(362) 
o 
