31 6 Veterinary Medicine. 



from this backward they slowly decrease in breadth, becoming 

 quadrate and finally square, through the ovulation and subse- 

 quent atrophy of the generative organs. The segments are not 

 detached, full of ova as in taeniae, but as the eggs are laid in the 

 bowels of the host the oviducts and segment both shrink, so that 

 when the segment finally drops off it is a mere little cube. The 

 total segments are about 4000, and the sexually mature ones are 

 behind the 600th. The sexual pores are not marginal but near 

 the centre of the ventral surface on a small tubercle, the male pore 

 in front and the female behind it. The oviduct is a tube folded 

 on itself to form a rosette toward the centre of the segment. Eggs 

 ovoid, with operculum at one end, 68 to 71 \>. long by 44 to 45 fi 

 broad. The eggs usually lie for months in water before hatching 

 out the globular ciliated embryo, which later sheds its covering 

 and appears as a six-hooked embryo, like that of the taenia. 

 The sexual organs are sometimes double. 



Habitat. Intestine of man, dog and cat. 



Distribution. The parasite is in the main confined to certain 

 localities, out of which it is only met with in individuals that 

 have visited the infested districts. These include the Western 

 Cantons of Switzerland and adjacent parts of France ; the north 

 of Italy ; the North Western and Northern provinces of European 

 Russia and Poland ; the Baltic shores of Finland, Sweden, and 

 Denmark ; Greenland ; Southern Russia ; Holland and Belgium ; 

 some points in Eastern Prussia, Pomerania, Rhenish Hesse, and 

 the cities of Berlin, I^ondon, Hamburgh, San Malo, Zurich, 

 Rome and Montpelier. 



These are in the main seacoast or lacustrine regions, or those 

 in which fresh fish from infested waters form a staple article of 

 diet. Yet from unknown causes it may disappear from formerly 

 infected districts. Odier claimed that one-fourth of the inhabi- 

 tants of Geneva suffered comparatively recently, yet to-day it has 

 virtually disappeared from the city. 



Larva. Plerocercoides. Braun found these larval forms in 

 the intestinal walls, muscles and other tissues of pike and turbot. 

 They show no generative organs and have the head invaginated. 

 Feeding them to dogs and cats which he carefully secluded from 

 other sources of infestment, he constantly developed the mature 

 worm in their intestines. Parona, Ferrara, Grassi and Rovalli 



