ECHINOSTOMID.E 267 



In man it is still more uncommon than the liver fluke, and has 

 hitherto only been observed seven times (Germany, Bohemia, Italy, 

 France, and Egypt) ; it may, however, have occurred more frequently, 

 and have been overlooked, as in slight infections it produces no 

 special symptoms. 



The intermediate host is still unknown. Leuckart for some time 

 held the opinion that small species of Planorbis from fresh water, 

 which contain encysted Distomata, were to blame, and he supported 

 his views by a feeding experiment which seemingly yielded positive 

 results ; this, however, is not definitely proved. Piana's statement 

 that small land snails are the intermediate hosts has also not been 

 proved. 



Family. Echinostomidae, Looss, 1902. 



Sub-family. Echinostominse, Looss, 1899. 



Genus. Echinostoma, Rud. 1809 ; Dietz, 1910. 



Fore-body not bulging. Greatest width at or behind the ventral 

 sucker. Oral sucker not atrophied. Collar kidney-shaped with a double 

 dorsally unbroken row of spines, terminating in four to five angle spines. 

 The border spines of the aboral series not larger than the oral. Skin 

 spined or smooth. Body elongated. Uterus long with numerous 

 transverse coils. Ventral sucker in the anterior quarter of body. Cirrus 

 sac small, almost completely in front of the ventral sucker. Testes round 

 or oval, smooth incurved or lobed, in the hinder half of body. Ovary 

 median or lateral in front of testes. Vitellaria from hinder margin of 

 ventral sucker to end of body. Eggs oval, 84 /A to 1 26 JJL by 48 p to 82 /z. 



The spines placed most ventrally, or those placed most medially 

 on ventral surface, are from differences of position or form termed 

 "angle" spines, the rest " border " spines. 



Type. Echinostoma echinatum, Rud. 



Echinostoma ilocanum, Garrison, 1908. 



Length 4 to 5 mm., breadth i to 1*35 mm., thickness 0*5 to 

 0-6 mm. The circum-oral disc 0*3 mm. broad, separated by a shallow 

 groove from the body. Crown of forty-nine spines and five to six 

 angle spines on each side continuous with an irregularly alternat- 

 ing series of fourteen spines on the dorsum. Largest spines are 

 34 fi long, 8 fi thick at the base. The remainder of the dorsal spines 

 are 24 //, by 6 //,. Skin thickly covered with scales on the margins 

 of the body as far back as the level of the hind testis. Oral sucker, 

 0-18 mm. ; ventral sucker, 0*4 to 0-46 mm. Its anterior border about 

 o'oy mm. from the anterior end. Pharynx 0*17 mm. long, OTI mm. 

 broad. Testes about mid-line of the body, much lobed ; the lobes of 

 the anterior testis run transversely, while the axis of the posterior testis 

 is longitudinal, as often occurs in the Echinostomida. Cirrus sac 



