ular lining* of the buceal caviU^ and the eliitinoiis teeth of the esopha- 
geal bulb disappear; the esophagus elongates. beeoim‘s thinner, and its 
three divisions become less distinct: the tail l)econi(‘s sliglitlv shorter 
and more blunt; the anus lies b() // from the tip of tin* tail. d'h(‘ onuin- 
Fig. 35. — Young hookworm {Afjcfiylostoiuaduodatalr) in fourth stagu. witli iirovisional lairral oapsule: 
r. (/., cervical gland; f/.. primordiimi of genital orgaii.M; u. x., nervous system; />. r., e.xerelory |M>ie. 
X 105. (.\fter Looss, IS'JT, p. '.fJl. lig. 1.) 
FtG. 30. — Provisional hnccal capsule (fourth stage) of a larval h(M>kwonn \ Affrfii/h/xlnntn ilioxlt imit ), 
about nine days after infection: y>. 5. /•., priinordinm <»f <letiidte hnccal capsule. X ahuiit fJO. (.\ fter 
Looss, iS'JT, i>. IfJl, lig. 5.) 
Fig. 37. — Young male hookworm {Ayrliiftoxtoma (hiuihnalr), nine days after infection a., aims; r. i/., 
cers’ical gland; genital tract; p. 5., priinordinm of hnrsa ; e.xiTetory canal ; xp., primor 
dinm of sj)icnles. X alxmt 105. (.\fter Looss, 1M*7, p. 022, tig. «>. i 
ism becomes more motih*, and contracts I’l-om its outer skin, thus form- 
ing the stage (tigs. /10-I>1 ) which has bt'cn (h‘sci*ilM*d as an ** encystation." 
but which in reality is simply a st'cond cedysis. 'Phis is the inf(*cting 
stage of the hookwoian. and (Mids the developimmt .so far as the free 
life is conceriH'd. No mort‘ food is taken. In some cases. howt‘ver, 
