32 TROPICAL MEDICINE AND HYGIENE 



pore does not carry the ring of " antlers" peculiar to 

 Heterophyes. The ovary and testes are not lobed. The 

 yolk glands are few and grouped into fairly large masses. 



PARAMPHISTOMID^E. 



In these the oral sucker is at one extremity and the 

 second sucker is more or less at the opposite extremity. 



The classification of this family has varied. According 

 to Stiles, these should be divided into two groups those 

 with cesophageal pouches and those without. The 

 pouches are not prominent features, or easy to see in 

 uncleared specimens. The classification is therefore to 

 that extent inconvenient. 



According to this grouping, both of the human species 

 of Paramphistomidce belong to the Cladorchince, as there 

 are lateral pouches on the oesophagus in both. 



The older division is based on external characters easy 

 to distinguish, and in man each of the two known 

 species belongs to a different division. 



(i) Amphistomum or Paramphistomum, 1 in which the 

 worm is more or less conical, the anterior edge being 

 narrow and the posterior broad, and Gastrodiscus in which 

 the posterior extremity is expanded into a broad, flattened 

 plate, the. anterior part appearing as a conical projection 

 springing from the dorsal surface of this plate. One of the 

 commonest of all flukes, the Amphistomum conicurn, is 

 found in enormous numbers in the stomachs of cattle in 

 most parts of the world. It does not appear to cause any 

 symptoms or disease in them. 



No true Amphistomum is known to occur in man. 

 The fluke originally termed Amphistomum watsoni is 

 described as a Cladorchis, as there are pouches on each 

 side of the oesophagus, and the genus is known as 

 Watson ius. 



Watsonius (Cladorchis) watsoni. This parasite occurs 



1 Paramphistomum, though the worse Greek, is the correct name 

 zoologically. 



