336 



YERMES. 



has a very irregular shape ; while that form which inhabits domestic animals, 

 E. scoliciparicng, more frequently retains the form of the simple vesicle. 

 Finally these echinococcus cysts frequently remain sterile, in which case they 

 are called Acephalocysts. Another and indeed pathological form is the so- 

 called multilocular Echinococcus, which was for a long time taken for a colloid 



cancer. It is also found in Mammalia (in 

 cattle), and here presents a confusing re- 

 semblance to a mass of tubercles. The 

 echinococcus disease (hydatid plague) was 

 widely spread in Iceland. This disease 

 likewise seems endemic in many places in 

 Australia. 



T, (Mierotcenia). The Cysticercoid form 

 is small, and has but little fluid in the small 

 portion which corresponds to the vesicle. 

 The head is small, but has a small club- 

 shaped or proboscis-like rostellum, and is 

 furnished with weak hooks. The eggs are 

 provided with several membranes. The 

 embryo is usually furnished with large 

 hooks. The Cysticercoid stages live prin- 

 cipally in Invertebrates (in Slugs, Insects, 

 etc.), and more rarely in cold-blooded 

 Vertebrates (the Tench). T. cucumcrina 

 Bloch, in the intestine of dogs (house 

 dogs). The Cysticercoid is entirely without 

 the caudal vesicle, and lives (according, to 

 Melnikoff and R. Leuckart) in the body 

 cavity of the Dog-louse (Trichodectes canis). 

 The infection with the Cysticercoids takes 

 place when the dog swallows the parasites 

 which are annoying him, while the para- 

 sites swallow the eggs contained in faeces 

 adherent to the hair of the dog. Nearly 

 allied is T. elliptic a Batsch. in the intestine 

 of the Cat, occasionally in that of Man. 

 T. nana Bilh. v. Sieb. in the intestine of 

 the Abyssinians. hardly an inch long. T. 

 flavojt)unctataWcin\. in the human intestine 

 (North America). The ("Jysticercoids of the 

 Meal-worm are probably developed into 

 tape-worms in the intestines of Mice and 

 Rats. 



In other partially unarmed Tcenias the 

 generative organs and development are as 

 yet not accurately known ; such are T. 



FIG. 274 a. Bothriocephalus latus (after 

 R. Leuckart). 



perfoliata Goeze, and T. plicata Rud. in the horse ; T.pectinata Goeze, in the 

 hare ; T. dispar Rud. in the frog ; T. expansa Im. in the ox. 



Fam. Bothriocephalidae. With only two suckers, which are weak and flat. 

 The generative organs, as a rule, open upon the surface of the proglottis. The 

 proglottides do not become detached singly. Hydatid stage represented by 

 an encysted Scolex. 



