CESTODA. 261 



been stated, as for instance, in the body cavity of the rabbit. T. tenui- 

 collis Rud. in the intestine of the weasel and the pole-cat, with a Cysticercus 

 which, according to Kiichenmeister, lives in the hepatic ducts of the field- 

 mouse. 



Echinococcifer "Weinl. The heads bud on special brood-capsules in such 

 a way that their imagination is turned towards the lumen of the vesicle 

 (Fig. 206). T. echinococcus v. Sieb. (Fig. 207) in the intestine of the dog, 

 3-4 mm. long, forming but few proglottides. The hooks on the head are 

 numerous but small. Its bladder-worm is distinguished by the great thick- 

 ness of the stratified cuticula. It lives as Echinococcus principally in the 

 liver and the lungs of man (E. hominis), and of domestic animals (E. veteri- 

 norum). The first form is also distinguished as E. altricipariens on account 

 of the frequent production of primary and secondary vesicles ; it usually 

 reaches a very considerable size, and has a very irregular shape ; while that 

 form which inhabits domestic animals, E. scolicipariens, 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 Echino- 

 coccus, which was for a long time taken for a colloid cancer. It is also 

 found in mammalia (in cattle), and here presents a confusing resemblance 

 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. 



Sub-fam. 2. Microtaeniinae. The rostellum is frequently absent, or 

 unarmed, or beset with small hooks. Development by means of Cysticercoids, 

 the vesicle having but little fluid, or being absent. The Cysticercoid lives 

 principally in invertebrates (slugs, insects, &c.), more rarely in cold-blooded 

 vertebrates (the tench). 



Sub-genus Dipylidium Leuck. With two sets of generative organs in 

 each segment. T. cucumerina, 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 (Tricho- 

 dectes canis). The infection with the Cysticercoids takes place when the 

 dog swallows the parasites which are annoying him, while the parasites 

 swallow the eggs contained in faeces adherent to the hair of the dog. 

 Nearly allied is T. clliptica, Batsch. in the intestine of the cat, occasionally 

 in that of man . 



Sub-genus Hymcnolepis Weinland. One set of generative organs in each 

 segment, opening on one side ; eggs with two smooth shells. T. nana 

 Bilh.-v. Sieb., in the intestine of the Abyssinians and in Sicily, hardly an 

 inch long ; probably identical with T. murina of the rat, the Cysticercoid 

 of which, according to Grassi and Rovelli, is able to develop in the 

 intestinal villi of its host, and then emerge to form a tape-worm in 

 the intestine (self-infection). T. flavopunctata Weinl., in the human in- 

 testine (North America). Also found by Grassi in Italy, and regarded as 

 identical with T. diminuta Rud. = leptocephala Crepl., of the rat. The 

 Cysticercoids of the meal-worm are probably developed into tape-worms 

 in the intestines of mice and rats. 



In other partially unarmed Taenias* the generative organs and develop- 

 ment are as yet not accurately known ; such are T. (Anoplocephala 



* See note on following page. 



