236 THE ANIMAL PARASITES OF MAN 



Family. Gastrodisciidae. 

 Genus. Gastrodiscus, Lkt., 1877. 



Acetabulum small, caudal and ventral margin raised, aperture relatively large. 

 Genital pore without sucker. Excretory pore post-vesicular, posterior to opening 

 of Laurer's canal. (Esophagus with muscular thickening ; caeca not wavy, long, 

 end post-equatorial and post-testicular. 



Male Geniialia. Testes two, branched pre-ovarial. 



Female genitalia. Ovary and shell gland post-testicular. Vitellaria extracaecal ; 

 uterus intercaecal ; Laurer's canal entirely prevesicular. 



Type. Gastrodiscus cegyptiacus, Cobbold, 1876. 



Gastrodiscus hominis, Lewis and McConnell, 1876. 1 

 Syn. : Amphistomum hominis, Lew. and McConn. 



Body, reddish in the fresh, 5 to 8 mm. long; posteriorly, 3 to 

 4 mm. broad. The disc has incurved edges which are interrupted in 

 front where it joins the anterior cylindrical portion and posteriorly 

 behind the ventral sucker. The disc itself and ventral surface are 

 covered with a number of (microscopic) papillae. 

 Pharynx provided with two diverticula or pouches. 

 The bifurcation of the gut lies sometimes above, 

 sometimes below the level of the genital pore. The 

 gut caeca end about the level of the centre of the 



4J| acetabulum. 

 dl Genital Pore. About the middle of the conical 



^^ anterior portion. (It appears to be surrounded by a 

 dJsfu l ?\~7,nTnii muscular sucker.) Leiper (1913) describes the ducts 

 Slightly magnified, as discharging at the tip of a large fleshy papilla, the 

 (After Lerc'cart.) sur f ace o f which bears cuttcular bosses. 



Testes much lobed, the anterior is smaller than the posterior and 

 lies at about the level where the anterior conical portion joins the 

 disc. The posterior testis just in front of the anterior margin of the 

 acetabulum separated from it by the ovary. The ovary, somewhat 

 oval in shape or slightly constricted in the middle, lies slightly to the 

 right of the median line. Dorsal to it lies the well-developed shell 

 gland, Laurer's canal opening in front of the excretory bladder. 

 The excretory bladder is a long sac with its opening at its posterior 

 extremity about the level of the middle of the acetabulum. The 



1 Leiper places this species in a new genus Gastrodiscoidcs. Genus Gastrodiscoidts, Leiper, 

 1913, distinguished from Gastrodiscus by : (i) large genital cone ; (2) position of genital orifice ; 

 (3) disc without papillae ; (4) testes one behind the other. 



