250 



THE ANIMAL PARASITES OF MAN 



0*3 mm. in diameter, or 0-4 by 0*3 mm. ; oesophagus, 0-02 mm. ; 



intestinal caeca convoluted, asymmetrical, the first part having the 



same structure as the oesophagus. The 

 cuticle is covered with spines in groups ; 

 the excretory pore opens at the posterior 

 end rather on the ventral surface, the excre- 

 tory ducts open into the elongated bladder 

 at the hind end near the pore. Genital 

 pore behind the ventral sucker and 

 median. Genital sinus 0*2 mm. long 

 with thick wall, ejaculatory duct 0*13 mm., 



pars prostatica 0*2 mm., seminal vesicle duct-like of irregular outline. 



Behind the sucker the ovary on the left, and the closely packed 



uterine coil on the right (though amphitypy of these two organs is 



common) ; the two irregularly lobed testes lie side by side posteriorly. 



Vitellaria extensive, leaving only a median dorsal and ventral space 



FlG. 149. Paragonimus 

 ringeri, Cobb. : to the right, 

 dorsal aspect ; to the left, ventral 

 aspect. Natural size. (After 

 Katsurada.) 



FK;. 150. Paragonimus ringeri, Cobb. : 

 diagram of the internal organs. a, oeso- 

 phagus ; 6, vitellaria (a portion only shown) ; 

 c, common genital duct ; d, shell gland with 

 oviduct, Laurer's canal and vitelline duct ; e, 

 ovary; f t vitelline receptacle; g, excretory 

 pore ; A, oral sucker ; z, pharynx ; k, gut*; /, 

 ventral sucker; m, uterine coils; n, vilellarian 

 ducts; 0, vas efferens ; /, testis. ( After Kubo.) 



FIG. I5OA. Paragonimus wesiermanii, 

 Kerb. : seen from the ventral surface. 

 Mouth, pharynx, intestinal caeca, at the sides 

 of which the vitellaria are observed. The 

 genital pore is behind the ventral sucker, and 

 next to it, on the left, the ovary ; on the right, 

 the uterus ; the two testes posteriorly ; the 

 excretory vessel in the middle. lo/l. (After 

 Leuckart.) 



free. Seminal receptacle probably absent ; Laurer's canal present. 

 The eggs are oval, brownish-yellow, fairly thin shelled, and measure 

 onf-an average 8i'2 p by 49-2 //,. 



The following species are also known : P. westermanii, Kerb., 

 1878, in the tiger, and P. kellicotti, Ward, 1908, in the pig, dog, and 



