582 



TREMATODA 



of the acetabulum, but not beyond it, wjiile that of A . sufrartyfex 

 reaches 075 mm., therefore it is not a member of the Echino- 

 stominae. 



Genus Echinostoma Rudolphi 1809. 

 Synonym,— FascioleUa Garrison, 1908. 



Definition. — -Echinostominse, with small elongated bodies, broader 

 anteriorly than posteriorly, with characteristic circumoral ring of 

 spines and with other spines on the body, and with large prominent 

 acetabulum. (Esophagus short, intestinal caeca unbranched. Ex- 

 cretory vesicle tubular. Genital pores anterior to the acetabulum. 

 Testes compact, situate in the median line one behind the other. 

 Cirrus and pouch well developed. Ovary compact ; no receptaculum 

 seminis; Laurer's canal present. Yolk glands well developed in 

 the posterior fifth of the body ; well-developed shell gland and uterus, 

 which lies between the ovary behind and the acetabulum in front. 

 Ova large and operculated. 



Remarks.— With regard to the position of Echinostoma, it should 

 be observed that some authorities do not classify it under the Fas- 

 ciolidae, but in a special family E chinos tomidae which we adopt. 



Type Species. — The type species is Echinostoma revolutum (P'roe- 

 lich, 1802), of which the synonym is Distoma echinatum Zeder, 

 1803. Another species of importance in tropical medicine is - 

 E. ilocanum (Garrison, 1908), 



Echinostoma ilocanum Garrison, 1908. 



Synonym.- — Fascioletta ilocana Gsirnson, igo8. 



History.' — Echinostoma ilocana was discovered and described by 

 Garrison, who in 1907 noticed peculiar eggs in the faeces of Philip- 

 pino prisoners in Bilibid Prison in Manila, and subsequently, after 

 treatment with male-fern, obtained a small number of trematodes. 

 Quite recently Odhner has shown that it belongs to the genus 

 Echinostoma, family Echinostomidae. 



Morphology.- — -Echinostoma ilocana is a very small trematode, measuring 

 4 to 6 millimetres in length by 0-75 to 1*35 millimetres in breadth and 0'5 to i 

 millimetre in thickness. Posteriorly it is attenuated. The acetabulum is 

 about three times the size of the oral sucker, which is either terminal or slightly 

 ventro-subterminal. The prepharynx is long, the pharynx globular; the 

 oesophagus short, bifurcating just anterior to the genital pore into the intes- 

 tinal caeca. The genital pores open separately a little behind the halfway 

 point between the pharynx and the acetabulum. 



The cirrus pouch is well developed, and contains posteriorly the vesicula 

 seminalis, into which open the vasa deferentia, and which gives rise to the 

 long coiled cirrus. Each testis shows an anterior and a posterior lobe. The 

 ovary is globular, the yolk glands well developed, and the uterus fairly 

 developed. Ova 88-8 to 114*7 long by 53-5 to 81-9 broad. 



Life-History.— Nothing is known of the life-history beyond the 

 fact that a miracidium hatches in about ten days after the eggs 

 have left the host. 



Habitat. — -The intestine of man in Luzon, in the Philippine 

 Islands. 



Pathogenicity. — -It is probable that the worm is non-pathogenic. 



