length (tig-. Hio ])r()visioiml ])ucc-al ca])Mil(‘ attains 4o // in diam- 
eter, and the mouth is l)ont slightly dorsad. Two pairs of t(‘ofh are 
visible at the base of the capsule— one pair sitiiat(‘d dorsallv. the other 
ventrally. During- this stage the animal incnaises in length and thick- 
Figs. 40-41. — Male and female hookworms {Agchylot^foiiKi iltindi unh i during; llif fourth rastiiiK of .sk.n 
14 to !.'> days after infection: aims; r. g., cervical j,d«nd: r. o. r., cuticle of old esophagus; r. 
cast skin; d. h. c., ilcfinite hticcal capsule; g., ftenital orpins; 1. g., larKO piUKlion, supplyiiu; the 
rays of the bursa; m. a., anal muscle; ?/. c. gl., ntmleus of cervical Khind. ;» r., c.xcretory pore 
]). b. c., provisional buccal capsule; r. m. ttg., retractor museks of spicules; s//., spicules; r., vulva. 
X 42. (After Looss, 1807, p. 024, fi^s. 0-10.) 
ne.ss, the inner organs becom(‘ hetttu- dendopt'd. the sexes become 
differentiated, and the detinitt' huceal eapsuh* forms at Iht' anterioi 
end. With these changes the parasite jirepares for its last -namely 
a fourth — eedysis, v>diich occurs about fourteen to liftt'en tlays afle‘ 
infection. 
